What is a DOI? & How it Used in Citations? [Digital Object Identifier Guide]

A DOI, short for ​Digital Object Identifier​, is a unique alphanumeric string used to identify and permanently link to a specific digital object—most often academic articles, research papers, datasets, and official reports. If you’re wondering what is a DOI and ​how DOI is used in citations​, the answer is simple: it acts like a permanent online fingerprint for scholarly content, ensuring that even if a document's location changes, its DOI remains a stable way to find it.

This tiny but powerful identifier plays a massive role in academic writing and research. Think of a DOI as a scholarly version of a URL that never breaks. While web addresses may change or disappear, a digital object identifier always points to the latest and most accurate version of a resource. That’s why including a DOI reference in your citations is now a standard practice in styles like APA, MLA, and Chicago. Not only does it show academic integrity and precision, but it also makes it easier for others to verify and locate your sources.
In this guide, you will explore:

• what is a DOI?
• How DOI Works?
• How Is a DOI Used in Citations?
• What Is a DOI Reference?
• Why DOIs Matter in Academic Writing?
• Digital Object Identifier Example & How to Find a DOI?

What is DOI？Revolution, Defination & Components

The Revolution of DOI

Before DOIs, researchers depended on URLs that could easily become obsolete. The development of the DOI system was a direct response to this issue, providing a stable reference point for digital documents. Over the years, this system has been refined and expanded, becoming an indispensable tool for librarians, publishers, and academics worldwide.

How to Define DOI？

DOI stands for ​Digital Object Identifier​. It’s essentially a persistent ID number used to identify academic and professional publications in the digital world. Unlike a regular link or URL, which might disappear or change over time, the DOI is ​permanent​. It's a code that ensures a digital work can always be found.

Each DOI is unique and leads to a specific piece of content, no matter where it's hosted. For example, even if the journal’s website changes or the article moves to a new domain, the DOI link remains valid. This ensures that the work can always be cited properly and accessed reliably.

How DOI Works: The Anatomy of a DOI

A typical DOI looks something like this: 10.1000/xyz123. It’s not just a random code. The structure of a DOI includes two parts:

• ​Prefix​: Assigned by the DOI registration agency (e.g., 10.1000)
• ​Suffix​: Assigned by the publisher, which identifies the specific item (e.g., xyz123)

Together, they form a unique code that represents a digital object. This structured approach not only ensures the uniqueness of each identifier but also provides a clear roadmap for locating and citing resources, making it a cornerstone of modern academic documentation.

When placed into a complete URL format, such as https://doi.org/10.1000/xyz123, it becomes clickable and directs users straight to the digital item.

This means that even if someone only has the DOI and not the full title or publication info, they can easily access the document by entering it in a DOI resolver or simply appending it to https://doi.org/. This is why many researchers and professors emphasize including the .doi or full DOI URL in bibliographies or footnotes.

How Is a DOI Used in Citations?

One of the most common questions from students is, “​How DOI is used in citations?​” The answer depends on which citation style you're using. But in all cases, the DOI is used to improve ​accuracy and accessibility​.

Let’s look at a few examples:

• ​APA Style (7th edition) ​:
  Smith, J. (2021). Title of the article. *Journal of Research*, 12(4), 34–45. https://doi.org/10.1234/abc567
• ​MLA Style (9th edition):
  Smith, John. "Title of the Article." *Journal of Research*, vol. 12, no. 4, 2021, pp. 34-45. https://doi.org/10.1234/abc567.
• ​Chicago Style​:
  John Smith, "Title of the Article," *Journal of Research* 12, no. 4 (2021): 34–45, https://doi.org/10.1234/abc567.

As you can see, the digital object identifier appears at the end of the reference. Some styles allow the use of just doi:10.1234/abc567, but modern practice usually prefers the full hyperlink. This makes the source easier to find and cite.

What Is a DOI Reference?

A DOI reference refers to any citation that includes the DOI of the cited work. Including a DOI makes your reference more reliable and future-proof. Without it, readers might face broken links or be unable to locate the source. Tt’s the most accurate and enduring way to point to a scholarly source online.

In fact, many journals require authors to provide DOIs for all references whenever available. Tools like Crossref, Scopus, JSTOR and PubMed help users easily find DOI numbers for journal articles, books, conference papers, and more.

Why DOIs Matter in Academic Writing

why are DOIs so important in academic writing​? Because they support ​academic integrity​. With a DOI, your readers can:

• Verify your sources
• Access full-text documents quickly
• Explore further readings from the same source

Moreover, using DOIs avoids confusion. If multiple articles have similar titles, the unique DOI guarantees readers find the exact one you cited. This clarity is especially crucial in scientific writing and evidence-based research, where precision matters.

In summary, DOI ensure trust, traceability, and access in scholarly communication.

Digital Object Identifier Example & How to Find a DOI

Below is a diverse list of DOI citation examples in ​APA​, ​MLA​, and Chicago styles using ​different types of source*, including ​journal articles, books, book chapters, conference papers​, and ​web-based scholarly content​.

APA Style DOI References (7th edition)

✅Journal Article

Example:

Smith, J. A., & Lee, M. T. (2021). Environmental ethics and climate action. ​Global Sustainability​, ​4​(2), 88–101. https://doi.org/10.1017/sus.2021.009

✅ Book

Example:

Brown, K. R. (2019). ​Modern genetics and gene expression​. Springer. https://doi.org/10.1007/978-3-030-23420-3

✅ Book Chapter

Example:

Jameson, P. (2020). Molecular models in education. In L. Huang (Ed.), Science education frontiers (pp. 134–155). Routledge. https://doi.org/10.4324/9781003054725-9

✅ Conference Paper

Example:

Thompson, L., & Zhou, D. (2023). AI-enhanced adaptive learning in STEM education. In Proceedings of the 2023 IEEE International Conference on Advanced Learning Systems (pp. 65–74). IEEE. https://doi.org/10.1109/ALS54567.2023.00012

✅ Online Report / Government Publication

Example:

World Health Organization. (2022). ​Mental health and COVID-19: Early evidence of the pandemic’s impact​. https://doi.org/10.35542/WHO.2022.30451

MLA Style DOI References (9th edition)

Format:
Author(s). ​Title of Source​. Title of Container, vol., no., Publisher, Year, pp. Pages. DOI.

✅ Journal Article

Example:

Patel, A., and Nina J. Gomez. “Urban Food Systems and Sustainability.” ​Journal of Urban Affairs​, vol. 45, no. 1, 2022, pp. 22–39. https://doi.org/10.1080/07352166.2022.2046781.

✅ Book Chapter

Example:

Carter, L. A. “Equity in Education Policy.” ​Global Policy and Practice in Education​, edited by Ramon Esposito, Routledge, 2021, pp. 112–128. https://doi.org/10.4324/9781003157686-8.

Chicago Style DOI References (Author-Date format)**

Format:
Author Last, First. Year. “Title of Work.” Title of Source Volume(Issue): Page range. https://doi.org/DOI.

✅ Journal Article

Example:

Nguyen, Alicia T., and Howard M. Stein. 2023. “Digital Access in Developing Nations.” Information Technology and Development 29(3): 215–234. https://doi.org/10.1080/02681102.2023.1884329.

✅ Book

Example:

Hollins, Grace. 2020. ​The Cultural Lens: A Study of Diversity in Practice​. Palgrave Macmillan. https://doi.org/10.1007/978-3-030-78910-8.

✅ Conference Paper

Example:

Desai, Vikram, and Lena Roberts. 2021. “Blockchain in Educational Credentials.” Paper presented at the International Symposium on Future Tech, Boston, MA, June 15–18. https://doi.org/10.1145/3457620.3457682.

Digital Object Identifier Examples (DOIs only)

Below are raw DOIs without full citations, for practice or citation tool input:

• 10.1016/j.cell.2020.11.036 – (Journal article in ​Cell​)
• 10.1007/978-3-030-12345-6 – (Springer book)
• 10.1109/ICSE.2022.00123 – (IEEE conference paper)
• 10.1038/s41586-022-04444-w – (Nature article)
• 10.1371/journal.pbio.3001234 – (PLOS Biology article)

Here’s a digital object identifier example you might find in a research paper:

https://doi.org/10.1016/j.jacc.2020.05.004

This DOI leads to a specific article in the ​Journal of the American College of Cardiology​. If you click the link or paste it into your browser, you'll land on the exact article page—no confusion, no broken links.

How to Find a DOI

• Check the first page of the article (PDFs often list the DOI near the title or abstract).
• Visit Crossref and search by article title or author.
• Use academic databases like PubMed, Scopus, or Web of Science—DOIs are usually included with each record.

Conclusion: Why Every Student Should Know What a DOI Is

To wrap up, if you’re serious about academic writing, you must understand what a DOI is and how it works. Whether you're writing an essay, thesis, or research paper, including the correct DOI in your references is no longer optional—it’s expected.

By now, you should confidently be able to answer questions like:

• What is a DOI and how is it used in citations?
• What is a digital object identifier and why is it important?
• How can I find and include a DOI in my reference list?

So next time you're formatting a paper or checking your references, don’t forget to double-check the DOI It might be a small detail, but it makes a big difference in the credibility and usability of your work.