DOI (digital object identifier) is an identification code for a journal article or other published works. The code was developed and introduced in 2000 by the International DOI Foundation (IDF) and is assigned by the publisher. A DOI is generated by a registration agency (Crossref) that contains an alphanumeric string beginning with “10” and a prefix of four or more numbers. The prefix is followed by a slash (/) and a suffix. The suffix is assigned by the publisher.
DOIs create unique uniform resource locators (URLs) that begin with https://doi.org/. For example, the DOI https://doi.org/10.1086/679716 will take you to the article titled “Scott’s Editing: History, Polyphony, Authority” by Robert Mayer, published in the May 2015 issue of Modern Philology. DOIs are used as electronic links to an article’s location and helps identify an article’s subject matter. They should always be used in your printed or electronic articles or in any other published materials. DOIs are usually placed on the first page of a journal article.
Crossref recently changed the DOI format to make it more web-friendly and secure. There is only a slight difference between the old and new formats, but be sure to check the new format and incorporate it into your references.
Citations and References
Citation and reference are two different things. A citation is a note within the text in parentheses and a reference is the full expansion of that note (all the information necessary to find the referenced material). You can cite passages or quotations and provide a citation for that within the text.
An example of in-text citation would be (Johnson 2017) in parentheses, or it could be just a numeral in brackets or superscript. A reference list would then list all the citations in alphabetical or numeric order, depending on the author guidelines.
Note that some style guides prefer to use the word “bibliography” instead of “references.” Be aware that these two words actually mean the same thing.
The following is a list of some style guides and how they prefer to list DOIs in their references.
American Psychological Association
The American Psychological Association (APA) style guide is used mainly in the social sciences. APA uses the “author-date” style for in-text citations (e.g., Johnson, 2017). Note the comma after the name and before the date.
When referencing the citations in the reference list, APA style is to include the DOI for all electronic media. The typical reference in APA style would use the following format:
Author, A. A., & Author, B. B. (Date of publication). Title of article. Title of Journal, volume number, page range. doi:0000000/000000000000 or http://dx.doi.org/10.0000/0000.
An example of a reference in APA style is as follows: (boldface type added for emphasis but not included in the reference):
Morey, C. C., Cong, Y., Zheng, Y., Price, M., & Morey, R. D. (2015). The color-sharing bonus: Roles of perceptual organization and attentive processes in visual working memory. Archives of Scientific Psychology, 3, 18–29. https://doi.org/10.1037/arc0000014.
Note the DOI is placed at the end of the reference.
American Medical Association
The American Medical Association (AMA) style is a guide used by medical researchers and those who are part of the medical and scientific publishing industry. The DOI included at the end of a reference in AMA style is similar to that in APA style, except that AMA does not require the preceding “https://” notation. An example of AMA reference style is as follows:
Coppinger T, Jeanes YM, Hardwick J, Reeves S. Body mass, frequency of eating and breakfast consumption in 9-13- year-olds. J Hum Nutr Diet. 2012; 25(1): 43-49. doi: 10.1111/j.1365-277X.2011.01184.x
Modern Language Association
The Modern Language Association (MLA) style is most commonly used in the liberal arts and humanities fields of study. MLA style is a bit different from APA or AMA in that its in-text citations include a page number (e.g., Johnson 15) instead of a date after the author name. If the author name is used within the text itself, only the page number is noted in the citation.
Although MLA does not require that a DOI or URL be used in a reference, it is a good idea to do so, especially when the journal or your professor prefers it. An example reference in MLA style is as follows:
Alonso, Alvaro, and Julio A. Camargo. “Toxicity of Nitrite to Three Species of Freshwater Invertebrates.” Environmental Toxicology, vol. 21, no. 1, 3 Feb. 2006, pp. 90-94. Wiley Online Library, doi: 10.1002/tox.20155.
Note that in MLA style, the full names of the authors are listed, not just the last name and initials. The names are arranged by the first author’s last name first and subsequent authors’ first then last names. The title of the work is in quotation marks.
No DOI?
Many older published papers might not have a DOI. If your article has no DOI, you can use the words “retrieved from” in your reference with a link to the journal’s homepage on the Internet. Do not use the web page that hosted the specific article. An example of an APA reference in which there is no DOI is as follows:
Author, A. A., & Author, B. B. (Date of publication). Title of article. Title of Journal, volume number. Retrieved from http://www.journalhomepage.com/full/url/.
As always, be sure to check author guidelines of your target journal for specific rules on citations and references.