What is a DOI and how can I find it?

Answer

DOI stands for Digital Object Identifier. A DOI is a string of numbers, letters and symbols used to permanently identify an article or document and link to it on the web. You can think of a DOI as a Social Security Number for an article. Unlike URLs, DOIs never change. 

This is what a DOI looks like: 10.2522/ptj.20090278 

You can create a link out of a DOI by adding the prefix: doi.org/ 

Here is a list of common places where you can find the DOI for an article:

  • First page of the electronic journal article
  • Near the copyright notice
  • Database landing page for an article
  • In the citation generated by the database
  • Online using the free DOI lookup

If you have a DOI and want to find the article, you can use the International DOI Foundation's Resolve a DOI Name feature.

Many citation styles prefer using DOIs over URLs to link back to an article because DOIs are more permanent. For more information about DOI's, check out our Citation Help guide. 

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  • Last Updated Sep 25, 2025
  • Views 123
  • Answered By Librarian

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