Tracking the Elusive DOI: -->

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Tracking the Elusive DOI:


By Melanie Brown, Dissertation Editor and Writing Faculty Member

If you have written even one reference list in APA 6th edition style—and if you have been a Walden student for more than a few weeks, chances are good that you have—then you have probably read about the DOI. What is this mysterious DOI? Some people say the letters individually (dee-oh-eye); others say doy (rhymes with joy or poi or “APA style leaves me an-noy-ed”). Either way, whatever you say, the DOI is here to stay. Savvy researchers like you need to learn what it is and how to use it.

DOI: What Is It?
A DOI is a digital object identifier—a fancy way of describing the unique number assigned to an electronic source. This number helps researchers locate a particular journal article quickly and efficiently. If a DOI has been assigned to a journal article you are citing for your paper, KAM, or proposal, then you must include that number in your reference list.

I can hear your questions now:

Savvy Student: “Wait a minute. I have 50 sources in my reference list. Do I have to include DOIs for all of them?”

Gentle Editor: “Only for electronic sources, such as journal articles you read in full-text or .pdf form.”

Savvy Student: “Wait another minute. Most of my sources are journal articles that I read in full-text or.pdf form. How do I know whether those 50 or 100 sources have DOIs?”

Gentle Editor: “By checking”

Savvy Student: “Look, Editor. I know you’re trying to help, but I don’t have much time to tinker with my reference list. Is easy to use?”

Gentle Editor: “You bet it is. Follow the simple steps below!”

DOI: How Do I Find It?
At, researchers can look up DOI numbers for online journal articles. Here’s how to use it:

1. Go to the Guest Query form (free DOI lookup) on

2. Scroll down to "Search on Article Title." Type the first author's name and the article title in the appropriate boxes and then click search. If your article has a DOI, it will appear. Voila! Thank you,

Note: If you need to locate many DOIs at the same time, it might be easier for you to use's Simple Text Query, which Anne outlines in her Tech Tip post.

DOI: How Do I Put It Into My Reference List?
Now that you have found a DOI for one of your journal articles, you have to include it in your reference list.

If showed the DOI as, it would look like this in a (fictional) reference:

Brown, M. (2011). Finding a DOI is not so hard after all. Journal for DOI Studies, 11, 9-14.

Notice that doi appears in lowercase letters. Notice also that there is no space between doi:#. Check out p. 191 and p. 198 in the APA Publication Manual for more examples of using the DOI correctly in your reference list.

If you have any questions or comments about or DOIs, post them here. Check out the Writing Center website, too, for more information about electronic sources (Citing Electronic Sources) and reference list formatting in APA style (Reference List Examples). Happy DOI hunting!


  1. Very helpful! Using CrossRef but the use of upper and lower case shown in many publications has been confusing - I will now go back and re-change them to lower case =)
    Thank you!

    1. Haha... we can empathize, Sue! APA can be so tricky sometimes. We're glad to hear that this blog post was helpful for you!

  2. Most of my sources do not have doi number

    1. Hi there! Many sources still do not have DOIs. This is completely fine! Follow the steps here to make sure you're citing correctly (