A Digital Object Identifier (DOI) is an internationally standardized locator for a digital source in any form. Beginning with the 8^th edition of the MLA Handbook, the three major styles now agree that the DOI is the preferred location element in a citation.

Why Are DOIs Recommended?

The DOI is unique and permanent. Publishers append DOIs to their content because it makes identification of their intellectual property clear and sharing of their content easy. In order to assign DOIs to their publications, companies pay a membership fee to a registration agency:

• Crossref (http://www.crossref.org/03libraries/index.html) manages scholarly and professional publications.
• Data Cite (https://www.datacite.org/mission.html) manages research data.
• Entertainment ID Registry (EIDR; http://eidr.org/) manages movies, television, and other “audiovisual object types that are relevant to entertainment commerce.”

Do All Sources Have a DOI?

Since there is a membership cost (http://www.doi.org/faq.html), not every publisher will use them. In database aggregators like EBSCO, ProQuest, and Gale, the DOI may appear in a page about the source, variously called Abstract Details, Records Display, or Detailed Record. However, finding a DOI for a source sometimes requires a bit of sleuthing. For example, if students copy and paste a database-created citation into their bibliographies, they should be aware that the DOI is not consistently given, even when it’s part of the vendor’s record for the source.

A journal may display the DOI in the header or footer on the first page of an article. Since the publisher has paid to join a DOI agency, its website will prominently display the DOI it has assigned to a journal article, a book, or even a chapter in a book .

As DOIs gain wider acceptance and citation styles require them, authors use them more frequently to point to related content in an abstract, a reference list or as footnotes for an article. However, when using a DOI to find a source, students should understand that the link will go to the publisher’s version, not the one in a database (the main exception is that Project MUSE will issue article level DOIs for journal articles they include in their database for publishers who want them). That means that students will have to do a second search if they want to find the source within your library’s databases. To help them, link to Simon Fraser University’s CUFTS (http://cufts2.lib.sfu.ca/MaintTool/public/search) so that students can search to determine which of your subscription databases has the article they need (CUFTS has another tool that enables you to select two databases and compare journal titles and coverage in order to identify the degree to which they overlap).

What Does the DOI Look Like in a Citation?

APA citations express DOIs as URLs http://dx.doi.org/ (followed by numbers), so that they can be used as hyperlinks in a browser. MLA and Chicago simply use doi: followed by the number.  (See the comparison in the figure at right)

What if Students Don’t See a DOI?

Since DOIs are not displayed consistently, you’ll want to advise students who are using scholarly sources to search Crossref, the largest registration agency, with over 80 million records. There are several ways to search Crossref:

• Students can do a simple title search to obtain the DOI (http://www.crossref.org/).
• When they have incomplete information, searchers can enter what they have into the “Free DOI Lookup” tool (http://www.crossref.org/guestquery/) to check for a DOI. 
• Once researchers register their e-mail to show they’re not an automated bot, they can copy and paste their entire reference list into the Simple Text Query box (http://www.crossref.org/SimpleTextQuery/) to simultaneously search for all DOIs.
• When researchers only have the DOI, they can use a reverse DOI Lookup (http://www.crossref.org/guestquery/) to find the full text of the source (even if the publication is defunct or at a new domain) and gather the complete information needed for the citation.

Add friction to your teaching by helping students appreciate the value of using persistent and unique location information.  For students and faculty who are using academic, scholarly, or professional sources, promote the use of DOIs as a reliable method for locating, reading, and citing digital objects.

References

The Chicago Manual of Style. 16th ed. Chicago: University of Chicago Press, 2010.

DataCite. "Our Mission." DataCite. Accessed July 22, 2016. https://www.datacite.org/mission.html.

Entertainment ID Registry Association. Home page. EIDR. http://eidr.org/.

Harper, Ben, and Natalie B. Milman. "One-to-one Technology in K-12 Classrooms: A Review of the Literature from 2004 through 2014." Journal of Research on Technology in Education 48, no. 2 (Winter 2016): 129-42. Accessed July 22, 2016. doi:10.1080/15391523.2016.1146564.

International DOI Foundation. "Frequently Asked Questions about the DOI® System." DOI. Last modified June 6, 2016. http://www.doi.org/faq.html.

Johns Hopkins University Press. "Frequently Asked Questions." Project MUSE. Accessed July 25, 2016. https://muse.jhu.edu/about/faq.html.

MLA Handbook. 8th ed. New York: Modern Language Association of America, 2016.

Publication Manual of the American Psychological Association. 6th ed. Washington: American Psychological Association, 2010.

Publishers International Linking Association. "Info for Libraries." Crossref.org. Last modified May 31, 2012. http://www.crossref.org/03libraries/index.html.

———. "Status." Crossref.org. Last modified July 22, 2016. http://www.crossref.org/06members/53status.html.

Simon Fraser University. "CUFTS: Open Source Serials Management: ReSearcher." Simon Fraser University Library. Last modified September 15, 2015. http://www.lib.sfu.ca/about/initiatives/researcher/cufts.

Note: This column is formatted according to The Chicago Manual of Style, 16th ed.