What is a DOI and where do I find it?

A DOI (digital object identifier) is a permanent identifier for an article, beginning with 10. It is usually printed on the first page of the PDF and on the article's landing page. If you cannot see one, search the title at search.crossref.org.

How do I cite a journal article with no DOI?

If you read it in print or in a library database such as JSTOR or EBSCOhost, APA ends the reference after the page range, with no URL. If you read it on an open website, add the article's URL. MLA names the database as a second container, and Chicago gives the database name or a stable URL.

What if the article has an article number instead of page numbers?

Use the article number in place of the page range. APA writes Article e4375, IEEE writes Art. no. e4375, and MLA and Chicago give the number where the pages would go.

Do I need the issue number?

Yes, whenever the journal has one. APA 7 includes the issue number for every journal, in parentheses after the volume, regardless of how the journal paginates.

Do I include the database name or a retrieval date?

Not in APA, unless the article is only available in that database. MLA asks for the database name as a container. Harvard asks for an access date with a URL but not with a DOI. Chicago does not require access dates for formally published articles.

How to Cite a Journal Article (With or Without a DOI)

Journal articles carry more identifying numbers than any other source: volume, issue, pages or an article number, and a DOI. Each style arranges those numbers differently, and that arrangement is where most errors happen.

What to Collect

All authors, in the published order
Year (and month, for IEEE)
Article title and journal title
Volume and issue
Page range, or the article number for online-only journals
DOI

Two real articles serve as worked examples. One is a classic with page numbers: Watson and Crick's 1953 paper in Nature. The other is an online-only article with nine authors and an article number: Piwowar and colleagues' 2018 study of open access in PeerJ.

Quick Reference by Major Style

APA (7th Edition)

Author, A. A., & Author, B. B. (Year). Title of article. Title of Journal, volume(issue), pages. https://doi.org/xxxx

Watson, J. D., & Crick, F. H. C. (1953). Molecular structure of nucleic acids: A structure for deoxyribose nucleic acid. Nature, 171(4356), 737–738. https://doi.org/10.1038/171737a0
Piwowar, H., Priem, J., Larivière, V., Alperin, J. P., Matthias, L., Norlander, B., Farley, A., West, J., & Haustein, S. (2018). The state of OA: A large-scale analysis of the prevalence and impact of open access articles. PeerJ, 6, Article e4375. https://doi.org/10.7717/peerj.4375

In-text: (Watson & Crick, 1953) and (Piwowar et al., 2018)

The article title is in sentence case with no italics or quotation marks. The journal title and the volume number are italic; the issue number is not. PeerJ has no issue numbers, so none appears.

MLA (9th Edition)

Author Last, First, and First Last. "Title of Article." Title of Journal, vol. x, no. x, Year, pp. xx-xx, DOI.

Watson, J. D., and F. H. C. Crick. "Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid." Nature, vol. 171, no. 4356, 1953, pp. 737-38, https://doi.org/10.1038/171737a0.
Piwowar, Heather, et al. "The State of OA: A Large-Scale Analysis of the Prevalence and Impact of Open Access Articles." PeerJ, vol. 6, 2018, e4375, https://doi.org/10.7717/peerj.4375.

In-text: (Watson and Crick 737) and (Piwowar et al.)

Chicago (18th Edition)

Footnote:

J. D. Watson and F. H. C. Crick, "Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid," Nature 171, no. 4356 (1953): 737, https://doi.org/10.1038/171737a0.
Heather Piwowar et al., "The State of OA: A Large-Scale Analysis of the Prevalence and Impact of Open Access Articles," PeerJ 6 (2018): e4375, https://doi.org/10.7717/peerj.4375.

Bibliography:

Watson, J. D., and F. H. C. Crick. "Molecular Structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid." Nature 171, no. 4356 (1953): 737–38. https://doi.org/10.1038/171737a0.

Author-date: Watson, J. D., and F. H. C. Crick. 1953. "Molecular Structure..." Nature 171 (4356): 737–38. In-text: (Watson and Crick 1953, 737)

The note cites the page you used; the bibliography gives the full range. Under the 18th edition, a note for a work with three or more authors names only the first author followed by "et al.", and the bibliography lists up to six authors. For more than six, such as the Piwowar article, list the first three followed by "et al." The 18th edition also says the month or season can usually be left out.

Harvard (Cite Them Right)

Surname, Initial. (Year) 'Title of article', Title of Journal, volume(issue), pp. xx–xx. Available at: https://doi.org/xxxx

Watson, J.D. and Crick, F.H.C. (1953) 'Molecular structure of nucleic acids: a structure for deoxyribose nucleic acid', Nature, 171(4356), pp. 737–738. Available at: https://doi.org/10.1038/171737a0

In-text: (Watson and Crick, 1953, p. 737)

With a DOI, no access date is needed because the link is permanent. With an ordinary URL, add (Accessed: 21 September 2026).

IEEE

[1] J. K. Author, "Name of paper," Abbrev. Title of Periodical, vol. x, no. x, pp. xxx–xxx, Abbrev. Month, year, doi: xxx.

[1] J. D. Watson and F. H. C. Crick, "Molecular structure of nucleic acids: A structure for deoxyribose nucleic acid," Nature, vol. 171, no. 4356, pp. 737–738, Apr. 1953, doi: 10.1038/171737a0.
[2] H. Piwowar et al., "The state of OA: A large-scale analysis of the prevalence and impact of open access articles," PeerJ, vol. 6, Feb. 2018, Art. no. e4375, doi: 10.7717/peerj.4375.

In-text: [1], [2]

IEEE abbreviates journal titles (IEEE Trans. Pattern Anal. Mach. Intell.), but one-word titles such as Nature and Science are written out. The IEEE Reference Guide lists up to six authors; with more than six, use the first author and "et al."

Articles Without a DOI

Many older articles and some smaller journals have no DOI.

Read in print or in a library database: APA stops after the page range. There is no URL and no database name, because database links do not work for readers outside your institution.
Read on an open website: add the direct URL of the article in every style.
MLA: add the database as a second container: JSTOR, www.jstor.org/stable/xxxxx.
Chicago: a stable URL or the database name is acceptable: JSTOR.
Harvard: Available at: URL (Accessed: date).

Check search.crossref.org before concluding there is no DOI. Older articles are often given one after publication, as the 1953 Watson and Crick paper was.

Article Numbers and Online-First Articles

Article numbers. Online-only journals (PLOS ONE, PeerJ, Scientific Reports) identify articles by number. Put the number where the pages would go, as in the Piwowar examples. If the PDF is paginated 1 to 23, those page numbers are still usable for pinpointing a quotation.

Advance online publication. For an article published online before it has a volume and issue:

APA: Author, A. A. (2026). Title of article. Title of Journal. Advance online publication. https://doi.org/xxxx
IEEE: A. A. Author, "Title of article," Abbrev. Journal, early access, Mar. 3, 2026, doi: xxxx.

Once the final version appears, update your reference with its volume, issue and pages.

Preprints are a different source type. See how to cite preprints and working papers.

Other Edge Cases

Twenty-one or more authors (APA). List the first 19, then an ellipsis, then the final author. See how to cite multiple authors.

No issue number. Leave it out. Do not write "(n.d.)" or "no. 0".

Special issues and supplements. APA cites an article in a special issue like any other article. For a supplement, write the volume as 12(Suppl. 2).

Articles in another language. APA gives the original title followed by an English translation in square brackets. IEEE adds "(in German)" after the title.

Abstract only. If you read only the abstract, say so in your text or find the full article. See how to cite sources you can't fully access.

Common Mistakes

Writing the DOI as "doi:10.xxxx" or "dx.doi.org" in APA 7, which wants https://doi.org/
Putting a period after a DOI or URL at the end of an APA reference
Capitalizing every word of the article title in APA, or using sentence case in MLA and Chicago
Italicizing the issue number in APA
Giving a database URL with a session or proxy string that no one else can open
Using "et al." in the APA reference list. It belongs only in the in-text citation.
Citing the page range in a Chicago footnote instead of the specific page

Sources for These Formats

APA Style, "Journal Article References" and "DOIs and URLs" (apastyle.apa.org)
MLA Handbook, 9th ed., and MLA Style Center, "Works Cited: A Quick Guide" (style.mla.org)
The Chicago Manual of Style, 18th ed., Citation Quick Guide, "Journal Article", and "What's New in the 18th Edition" (chicagomanualofstyle.org)
Pears and Shields, Cite Them Right, Harvard section on journal articles
IEEE Reference Guide, version 3.28.2025, section M, "Periodicals"

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