Correction for Johnstone and Bshary, Evolution of spite through indirect reciprocity

How can cooperation persist in the face of a temptation to 'cheat'? Several recent papers have suggested that the answer may lie in indirect reciprocity. Altruistic individuals may benefit by eliciting altruism from observers, rather than (as in direct reciprocity) from the recipient of the aid they provide. Here, we point out that indirect reciprocity need not always favour cooperation; by contrast, it may support spiteful behaviour, which is costly for the both actor and recipient. Existing theory suggests spite is unlikely to persist, but we demonstrate that it may do so when spiteful individuals are less likely to incur aggression from observers (a negative form of indirect reciprocity).

Finding and correcting citations often seems like an impossible task. Even when the references have been imported from a database into a reference management system such as EndNote® or RefWorks, the information can be confusing. Some databases, including PubMed, reformat citations for consistency while others, notably Google Scholar, just harvest from other websites. It is not unusual to find differences in an article's title, authors, journal name, and so forth. Add in the “to err is human” factor, and references can be difficult to track down. This is when the Digital Object Identifier (DOI) may save the day. Uniform Resource Locators (URL), including those considered permanent, were long considered the best way to link to resources. In a publishing world where acquisitions and mergers have become the norm, URLs change and the links are lost. “Link-rot,” a term for bad or lost URLs, happens frequently. In a late 2006 study, Bugeja and Dimitrova examined the half-life of online citations in nine journalism journals published since 2000. From those journals 53% of the online citations were dead. They calculated the half-life of citations for these journals to be 3.95 years (Bugeja & Dimitrova 2010). Another 2006 study conducted by a group at the National Library of Medicine examined URLs in MEDLINE abstracts from 1994 to 2006. The authors randomly accessed over ten thousand URLs once a day for thirty days and found that 81% of the links were available most of the time, but only 78% contained the intended information. Another 3% were available some of the time, and 16% of the URLs were “dead” (Ducut, Liu & Fontelo 2008). Both groups suggested that the DOI could be the key to adding stability to the world of electronic citations if they were used universally. DOIs came rushing to the attention of writers and publishers in 2010 with the advent of the American Psychological Association's (APA) Version 6. The sixth edition of APA requires a DOI, if available, for articles and electronic books. Since APA began using the DOI as the key identifier, DOIs have proliferated and become important parts of citations. Other bibliographic formats, including the American Medical Association's 10th edition, have also added the DOI as a desired element. In the mid-1990s, the Association of American Publishers' Enabling Technologies Committee developed the DOI as a way to address several issues including changing ownership rights (Rosenblatt 1997). Publisher-assigned DOIs continue to identify an item even if it moves or changes ownership. A 2007 article in this publication described the publisher Blackwell's use of the DOI (Wates 2007). The number of items with DOIs has grown rapidly over the last decade. According to the International DOI Foundation (IDF) information, more than 55 million DOI names have been assigned (IDF 2012a). IDF lists nine DOI registration agencies around the world (IDF 2012b) but perhaps the best known is CrossRef (http://www.crossref.org/). Note the following citation: Nelson D P, LeMaster T H, Plost G N & Zahner M L (2009) Recognizing sepsis in the adult patient. American Journal of Nursing 109, 40–46. As given, this information requires an author or title search in a database. By adding the DOI (https://doi.org/10.1097/01.NAJ.0000346928.90369.10), the article can be found directly in many databases, and the citation is immediately retrieved. This reduces the amount of time and frustration in tracking down citations. Nelson D P, LeMaster T H, Plost G N & Zahner M L (2009) Recognizing sepsis in the adult patient. American Journal of Nursing 109, 40–46. https://doi.org/10.1097/01.NAJ.0000346928.90369.10 One catch in DOI searching is that all not databases have added a DOI search function. For example, CINAHL and other EBSCOhost databases lack this functionality. When contacted, an EBSCO representative indicated there was currently an “enhancement request to make DOI a searchable field in EBSCOhost databases.” EBSCO is not the only database producer struggling to incorporate DOIs in their searchable and downloadable fields. The number of databases incorporating DOI fields and search capabilities is consistently increasing. PubMed, Google Scholar, Web of Knowledge, and Scopus are widely used databases providing directly searchable DOI data fields that will also be downloaded as part of the citation into reference management programs. Even if the DOI is not available from a database, it is often seen on the article itself and can be added manually to the bibliographic manager or a document. This approach still adds the “to err is human” factor. Another way to track down a DOI is to use the search feature in CrossRef, which allows for author and title searching. Rather than going to the CrossRef Home page, it is easiest to use the free DOI guest search http://www.crossref.org/guestquery/, which goes directly to the search page. An increasing number of publishers are now also adding DOIs to ebooks and ebook chapters. Perhaps the most exciting “new” use of the DOI is ebook chapter DOIs, which will make searching and citing much easier. Below is an example an ebook with a DOI in APA format: Hendrick, J. (2010). Law and ethics in children's nursing [electronic resource]. Chichester, West Sussex; Ames, Iowa: Wiley-Blackwell. https://doi.org/10.1002/9781444320428 Note that the DOI contains the Online ISBN: 9781444320428. This book also offers chapter level DOIs. Hendrick, J. (2010). Law and ethics in children's nursing [electronic resource]. In Law and ethics in children's nursing. Chichester, West Sussex; Ames, Iowa: Wiley-Blackwell. https://doi.org/10.1002/9781444320428 Looks nice, but the issues are the same as in the early days of article DOIs. While the publishers are including the DOI, not all catalogs or aggregators are adding the DOI and making them searchable. To prepare the above citation, the DOI was copied from information in the ebook and pasted into the RefWorks DOI field. This adds another step to reference checking and formatting. However, these issues will likely change as the new guidelines are accepted. and book DOIs become used more widely. At this point in time, when almost every article is available in electronic format, the article DOI is appreciated and widely used. Now the “ball is rolling” to increase book DOIs. The visions of having the DOI as a “white knight” may be coming closer to reality. Look for a future filled with DOIs. Julia Shaw-Kokot, RN, MSLS, AHIP, Assistant Department Head for User Services, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA. Email: jsk@med.unc.edu

Now I am become DOI, destroyer of gatekeeping worlds

The classification of living things depends upon the literature. Access to this literature is essential to taxonomic research and to our understanding of biodiversity. There have been tremendous efforts to digitise the world’s biodiversity literature; the Biodiveristy Heritage Library (BHL) alone has uploaded over 54 million pages, all of which is freely accessible online. Our scientific literature is far more accessible than it has ever been, but that does not mean it is easily discoverable. Much of the taxonomic literature online remains outside the linked network of scholarly research. But that is rapidly changing. Taxonomic aggregators are an invaluable source of authoritative information on species names and their hierarchical classification. It is critical that this information includes citations for taxonomic descriptions, that these citations link to the published literature online and that (wherever possible) the citations include DOIs (Digital Object Identifiers). The DOI is an essential part of a publication’s bibliographic metadata and should be included (as a live link) in any reference to that content. However, the definitive (DOI’d) versions of recent publications are frequently behind paywalls. And, while much of the historic literature available online is open access, commercial publishers are uploading out-of-copyright publications onto their own websites, assigning DOIs to “their” definitive versions (the versions that must be cited in other publications, as per DOI requirements) and then locking the defintiive versions behind paywalls. This is perfectly within their rights. DOIs may be assigned to legacy publications retrospectively, providing that: a) the party assigning them owns the rights for the content, or has permission from the rights holder to assign a DOI, and b) the publication does not already have a DOI. If there are no rights attached to a piece of content, anyone can assign a DOI to it. This means that citation traffic from the bibliographies of current publications is increasingly directed towards commercial publishers’ websites, rather than towards open access versions, such as those freely available on the Biodiversity Heritage Library (BHL). However, taxonomic aggregators are not bound by the same obligations as publishers and may therefore choose to link to any online version of a publication (although the DOI should still be included in the citation). Many taxonomic aggregators link to the literature available on BHL. The taxonomic name profiles in EOL (Encyclopedia of Life), GBIF (Global Biodiversity Information Facility) and ALA (Atlas of Living Australia) each contain a BHL bibliography: a list of links to the pages in BHL that contain an identified mention of that taxon name. However, the lists of returned results can be long, and they may or may not include the citations for accepted names, synonyms and taxon concepts. Some biodiversity aggregators feature these key citations on the names pages (or tabs) of taxon profiles. However, where these do exist, they are usually plain text rather than links. BHL is now registering DOIs for the content it hosts and is creating landing pages for articles, containing the full bibliographic metadata, including (where applicable) the DOI. Articles are now discoverable by article title, keywords within titles (scientific names, locations, traits, etc.), author names and DOIs, and can be easily linked to (via their landing pages) by other parties. This paper will examine the issues, benefits and complexities associated with linking to definitive versions, the difference between easy and open access, the ethics of putting out-of-copyright content behind paywalls, and the future of creating order amongst the massively expanding resource of literature online.

Wikipedia is a gateway to knowledge. However, the extent to which this gateway ends at Wikipedia or continues via supporting citations is unknown. Wikipedia’s gateway functionality has implications for information design and education, notably in medicine. This study aims to establish benchmarks for the relative distribution and referral (click) rate of citations—as indicated by presence of a Digital Object Identifier (DOI)—from Wikipedia, with a focus on medical citations. DOIs referred from the English Wikipedia in August 2016 were obtained from Crossref.org. Next, based on a DOI’s presence on a WikiProject Medicine page, all DOIs in Wikipedia were categorized as medical (WP:MED) or non-medical (non-WP:MED). Using this categorization, referred DOIs were classified as WP:MED, non-WP:MED, or BOTH, meaning the DOI may have been referred from either category. Data were analyzed using descriptive and inferential statistics. Out of 5.2 million Wikipedia pages, 4.42% (n = 229,857) included at least one DOI. 68,870 were identified as WP:MED, with 22.14% (n = 15,250) featuring one or more DOIs. WP:MED pages featured on average 8.88 DOI citations per page, whereas non-WP:MED pages had on average 4.28 DOI citations. For DOIs only on WP:MED pages, a DOI was referred every 2,283 pageviews and for non-WP:MED pages every 2,467 pageviews. DOIs from BOTH pages accounted for 12% (n = 58,475). The referral of DOI citations found in BOTH could not be assigned to WP:MED or non-WP:MED, as the page from which the referral was made was not provided with the data. While these results cannot provide evidence of greater citation referral from WP:MED than non-WP:MED, they do provide benchmarks to assess strategies for changing referral patterns. These changes might include editors adopting new methods for designing and presenting citations or the introduction of teaching strategies that address the value of consulting citations as a tool for extending learning.

Digital object identifiers (DOIs) have become essential tools in academic publishing for linking and identifying digital objects. This review examines the structure and assignment process of DOIs, shedding light on their critical importance in scholarly communication. DOIs consist of a unique alphanumeric string, including a prefix and a suffix, which serves as a persistent link to digital objects. By providing a standardized identifier, DOIs enhance the discoverability, accessibility, and referencing of various digital objects, including journal articles. The DOI also plays a crucial role in article promotion. With a DOI, authors, publishers, and researchers can effectively share and promote their articles, facilitating their discoverability in academic and research communities. However, challenges may arise with DOIs, such as non-functional links. This review provides troubleshooting tips for resolving such issues, including checking for typographical errors, validating the source, and seeking assistance from the DOI registration agency or the publisher.

Specimens are often mentioned in scholarly publications or data infrastructures by referencing the local identifiers attached to the objects held in specimen collections. However, these are often only unique to the issuing institution and not resolvable. Transforming these into globally unique identifiers, such as the 'Darwin Core Triplet' constructed from codes that specify the institution, the collection and the accession or catalog number, is an imperfect solution. These cannot be unambiguously validated nor be dereferenced (Guralnick et al. 2015, Groom et al. 2019), are vulnerable to human error, and rely on accession numbers that sometimes change over time. Earlier approaches to give specimens globally unique and resolvable identifiers had limited success (Page 2009). Attaching labels with new identifiers is too costly and time consuming, apart from digital infrastructure challenges. The Digital Extended Specimen is a new object on the internet, containing all known information about the specimen, thus acting as a surrogate for the physical object. To distinguish it from its physical counterpart, it needs a new identifier, which also provides a solution to unambiguously and persistently refer to specimens. Digital specimens get Digital Object Identifiers (DOIs) and Persistent Identifiers, in the infrastructure developed in the BiCIKL project (see deliverable D7.1 and this blog post). Ties to these accession or catalog numbers of physical specimens, allow these local identifiers to change over time, while still persistently resolving to the digital object. DOIs guarantee global uniqueness, persistence and reliable resolution through the oversight of the DOI Foundation and its registration agencies (RAs). DiSSCo, Distributed System of Scientific Collections, is creating a partnership with DataCite RA, where both partners invest to provide Digital Specimen DOIs and enhance their findability, leveraging from their metadata services. This aids the potential of Digital Specimen DOIs to reliably create links with data in other infrastructures, cite individual specimens, and improve the FAIR-ness (Findable, Accessible, Interoperable, Reusable) of specimen data worldwide. We will present how to use these new DOIs in practice. The use of Digital Specimen DOIs in a publication to reference a specimen is already piloted (Deeleman-Reinhold et al. 2024). All specimen records cited in the publication have been assigned a DOI that points to a digital representation of the specimen, the Digital Specimen, which can evolve over time to become a digital extended specimen by digitally linking it to relevant ecological, environmental, and related data such as the publication itself. The DOIs redirect both to a machine readable and a human readable version and include metadata in the DOI record for machine actionability that is also findable in DataCite Commons. The Crosscite citation formatter offers guidance to users how to cite a Digital Specimen DOI, similar to DOIs that refer to other works.

<p>Only four years after the implementation of digital object identifiers (DOIs) for unambiguously identifying and linking to online articles, the first DOI for digital datasets was registered in 2004. Originally developed with the purpose of providing permanent access to (static) datasets described in scholarly literature (to allow reproducibility and scrutiny of research results), DOIs today are increasingly used for dynamic datasets (e.g. time series from observational networks, where new data values are added frequently given that the originally published data will not change), collections or networks. These DOIs (and other persistent identifiers) are mainly assigned for providing a citable and traceable reference to various types of sources (data, software, samples, equipment) and means of rewarding the originators and institutions.</p><p>As a result of international groups, like the Coalition for Publishing Data in the Earth and Space Sciences (COPDESS) and the Enabling FAIR Data project, datasets with assigned DOIs are now fully citable in scholarly literature - many journals require the data underlying a publication to be available before accepting an article. Initial metrics for data citation are available and allow data providers to demonstrate the value of the data collected by institutes and individual scientists – which makes them even more attractive.</p><p>This is especially relevant in the framework of evaluation criteria for institutions and researchers, that usually only consider scientific output in the form of scholarly literature and citation numbers. Compared to other scientific disciplines, geodesy researchers appear to be producing less “countable scientific” output. Geodesy researchers, however, are much more involved in operational aspects and data provision than researchers in other fields might be. Geodesy data and equipment therefore require a structured and well-documented mechanism which will enable citability, scientific recognition and reward that can be provided by assigning DOI to data, data products and scientific software.</p><p>To address these challenges and to identify opportunities for improved coordination and advocacy within the geodetic community, the International Association of Geodesy’s (IAG) Global Geodetic Observing System (GGOS) has established a Working Group on “Digital Object Identifiers (DOIs) for Geodetic Data Sets”. The GGOS DOI Working Group (with more than 20 members) officially started with a first meeting during December 2019, co-located to the AGU Fall Meeting. Beginning with an assessment of DOI minting strategies that are already implemented, the GGOS DOI Working Group is designated to establish best practices and advocate for the consistent implementation of DOIs across all IAG Services and in the greater geodetic community.</p>

NASA’s Earth Science Data and Information System (ESDIS) Project began investigating the use of Digital Object Identifiers (DOIs) in 2010 with the goal of assigning DOIs to various data products. These Earth science research data products produced using Earth observations and models are archived and distributed by twelve Distributed Active Archive Centers (DAACs) located across the United States. Each data center serves a different Earth science discipline user community and, accordingly, has a unique approach and process for generating and archiving a variety of data products. These varied approaches present a challenge for developing a DOI solution. To address this challenge, the ESDIS Project has developed processes, guidelines, and several models for creating and assigning DOIs. Initially the DOI assignment and registration process was started as a prototype but now it is fully operational. In February 2012, the ESDIS Project started using the California Digital Library (CDL) EZID for registering DOIs. The DOI assignments were initially labor-intensive. The system is now automated, and the assignments are progressing rapidly. As of February 28, 2017, over 50% of the data products at the DAACs had been assigned DOIs. Citations using the DOIs increased from about 100 to over 370 between 2015 and 2016.

frequently through the DOI system. However, the report only includes papers that are accessed through the DOI proxy server; that is, only those papers accessed by clicking DOI addresses or by entering DOI addresses of the specific articles are included, not the papers looked up by clicking their titles on journal websites or identified through searches of databases such as PubMed, ScienceDirect, and Ovid. Therefore, the resolution report does not fully reflect how many times each paper was accessed. Rather, it indirectly demonstrates that papers are likely to have been accessed often in general when they have been accessed often by DOI search. We analyzed a total of 320 articles with assigned DOIs published in APS during a two-year period (2012-2013) to determine how frequently they were accessed through the DOI proxy server from January 2012 to March 2014. We found the following: One paper was accessed more than 199 times; four papers 100-199 times; 6 papers 50-99 times; 22 papers 30-49 times; and 106 papers 1-29 times. Thus, 139 papers were accessed at least once. Of the 33 papers that were accessed 30 or more times, original articles and reconstruction were the most common article type and topic, respectively (Tables We also examined how many times the 139 articles accessed using

<p>Data publications with digital object identifiers (DOI) are best practice for FAIR sharing data. Originally developed with the purpose of providing permanent access to (static) datasets described in scholarly literature, DOI today are more and more assigned to dynamic data. These DOIs are providing a citable and traceable reference of various types of sources (data, software, samples, equipment) and means of rewarding the originators and institutions. As a result of international groups, like the Coalition on Publishing Data in the Earth, Space and Environmental Sciences (COPDESS) and the Enabling FAIR Data project, data with assigned DOIs are fully citable in scholarly literature and many journals require the data underlying a publication to be available – even before accepting an article. Initial metrics for data citation allows data providers to demonstrate the value of the data collected by institutes and individual scientists.</p><p>This is especially relevant for the geodesy, because, geodesy researchers are often much more involved in operational aspects and data provision than researchers in other fields might be. Therefore, compared to other scientific disciplines, geodesy researchers appear to be producing less “countable scientific” output. Consequently, geodesy data and equipment require a structured and well-documented mechanism which will enable citability, scientific recognition and reward that can be provided by assigning DOI to data and data products.</p><p>To address these challenges and to identify opportunities for improved coordination and advocacy within the geodetic community, the International Association of Geodesy’s (IAG) Global Geodetic Observing System (GGOS) has established a Working Group on “Digital Object Identifiers (DOIs) for Geodetic Data Sets” in 2019. This Working Group is designated to establish best practices and advocate for the consistent implementation of DOIs across all IAG Services and in the greater geodetic community.</p><p>The main objectives and activities of this working group are:</p><ul><li>(1) to identify what the community needs from consistent usage of DOIs for data in terms of being able to discover data, permanently cite data, and acknowledge the data providers</li> <li>(2) to develop recommendations for DOI minting strategies for different geodetic data types and granularity across IAG Services (static, dynamic, observational data, data products, combination products, networks)</li> <li>(3) to develop recommendations for a consistent method for data citation across all IAG Services, to support data providers, and to provide quantitative support detailing the use of geodetic datasets and other resources.</li> <li>(4) to develop recommendations for connecting metadata standards for data discovery (e.g. DataCite, ISO19115) with community metadata standards (GeodesyML, Station Logs)</li> </ul><p>This presentation will provide an update on recent topics and first recommendations from the GGOS DOI Working Group.</p>

In the academia it is “publish or perish”. At some stage, the number of international publications also counts. It may however sound ridiculous that referencing may hinder an author from being able to publish in some international journals. This is because such international journals request for the Digital Object Identifier (DOI) of references cited by authors. Regrettably, most authors have never heard about DOI before, let alone being familiar with it. DOI is a standard numbering system like ISBN/ISSN. It is a unique code preferred by publishers in the identification and exchange of the content of a digital object such as journal articles, web documents, or other intellectual property. This article is an eye opener to the features and benefits of DOI, anatomy of a DOI name, citing DOI in references and locating DOI of references.Key words: Digital object identifier (DOI), authors, referencing.

The adoption of journal policies requiring authors to include a Data Availability Statement has helped to increase the availability of research data associated with research articles. However, having a Data Availability Statement is not a guarantee that readers will be able to locate the data; even if provided with an identifier like a uniform resource locator (URL) or a digital object identifier (DOI), the data may become unavailable due to link rot and content drift. To explore the long-term availability of resources including data, code, and other digital research objects associated with papers, this study extracted 8,503 URLs and DOIs from a corpus of nearly 50,000 Data Availability Statements from papers published in PLOS ONE between 2014 and 2016. These URLs and DOIs were used to attempt to retrieve the data through both automated and manual means. Overall, 80% of the resources could be retrieved automatically, compared to much lower retrieval rates of 10–40% found in previous papers that relied on contacting authors to locate data. Because a URL or DOI might be valid but still not point to the resource, a subset of 350 URLs and 350 DOIs were manually tested, with 78% and 98% of resources, respectively, successfully retrieved. Having a DOI and being shared in a repository were both positively associated with availability. Although resources associated with older papers were slightly less likely to be available, this difference was not statistically significant, suggesting that URLs and DOIs may be an effective means for accessing data over time. These findings point to the value of including URLs and DOIs in Data Availability Statements to ensure access to data on a long-term basis.

The Japanese Society of Applied Entomology and Zoology was established in 1957 as a result of a merger between the Japanese Society for Applied Zoology, founded in 1929, and the Nippon Society of Applied Entomology, founded in 1938. Applied Entomology and Zoology was inaugurated as the journal of the Japanese Society of Applied Entomology and Zoology in 1966. The journal publishes articles concerned with applied zoology, applied entomology, environmental entomology, agricultural chemicals, and pest control, and covers aspects of both fundamental and applied entomology and zoology. Applied Entomology and Zoology continues to be a leader in these scientific fields not only in Japan but across Asia. Integrated pest management and conservation of biodiversity are two important aspects of integrated crop management for the future. Applied Entomology and Zoology covers both those scientific fields and is expected to be an internationally important journal. The number of submissions from other countries has been increasing year by year in tandem with its growing international recognition. The Japanese Society of Applied Entomology and Zoology has decided to publish Applied Entomology and Zoology with Springer from 2011 to reach a wider audience and to make it easier to submit papers and to access from other countries as an international journal. We hope that publication with Springer will help Applied Entomology and Zoology to attract more international attention and higher quality papers. We are convinced that quick publication is essential to achieve this aim. The editors of Applied Entomology and Zoology and Springer are pleased to announce a new service for our authors and readers: Online First, the quick online publication of articles shortly after receipt of the corrected proofs. Online First publishes accepted articles in electronic form prior to their appearance in the print version of the journal, eliminating the delay necessary for the completion of an entire issue, printed or electronic. The electronic version of Applied Entomology and Zoology used to appear at the same time as the print journal, but from now on the electronic version of all articles will be available to subscribers via the Internet weeks before the printed version appears. This means a significant reduction in publication time. It will no longer be necessary for manuscripts to wait until the next available print issue. As each article becomes ready for Online First publication, it will be published on the Web with its own publication date. Each article will receive a permanent, unique international identification code, the digital object identifier (DOI), which is registered with the International DOI Foundation (http://www.doi.org). Contributions published Online First but not yet available in print may be cited by journal title and DOI only. Furthermore, the DOI forms part of the article’s URL (Web address) and can be used to access the article before the print version has appeared (e.g., http://dx.doi.org/10.1007/s13355-010-0009-7). The DOI is never changed and can be used, for example, to create hyperlinks between Online First articles. The print version also includes the DOI and date of online publication. The appearance of an article on Online First constitutes official publication, so articles cannot subsequently be changed or withdrawn. Any corrections deemed necessary will be in the form of an Erratum, which will be hyperlinked to the article.

The editors of Modern Rheumatology and the publisher are pleased to announce the introduction of Online First service, the quick online publication of articles shortly after receipt of the corrected proofs. Online First publishes accepted articles in electronic form prior to their appearance in the printed journal, without having to wait for the completion of an entire issue, printed or electronic. The electronic version of all articles will be available to subscribers via the Internet weeks before the printed version appears. This means a significant reduction in publication time. It will not be necessary for manuscripts to wait until the next available print issue. As each article becomes ready for Online First publication, it will be published on the Web with its own publication date. Each article will receive a permanent, unique international identification code, the digital object identifier (DOI), which is registered with the International DOI Foundation http://www.doi.org. Contributions published Online First, but not yet available in print, may be cited by journal title and DOI only. Furthermore, the DOI forms part of the article’s URL (Web address) and can be used to access the article before the print version has appeared. The DOI is never changed and can be used, for example, to create hyperlinks between Online First articles. The print version also includes the DOI and date of online publication.