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Citing Your Sources: Digital Object Identifier (DOI) and Permalink

DOIs, Permalinks, and UD EZproxy

DOI — identifies an electronic object, article, book chapter, etc.

Permalink — a URL that is a permanent link to a digital object

Contrast to a "regular" URL which links to a location on the web. If that object is moved, the link is broken.

If the electronic object is available for free, the permalink will open or access the object.

If the electronic object is available only by license or subscription, you will receive an error message that you are not allowed to access the item (e.g., electronic journal article) unless you or your library has access to the article.

UD EZproxy (needed for off-campus access). If the library subscribes to or licenses the journal article you need to identify yourself as an authorized UD student, faculty, or staff.

How to Create a Link Using a DOI


Type this prefix:


A link formed with a doi (or other permanent identifier) is a permalink or permanent link.

Using a DOI to retrieve an item is sometimes called resolving a DOI.

Another method of creating a permalink is to either type or paste the DOI into a "resolver box" on:

More Information About DOIs

Articles predating the DOI system

Scholarly publishers digitizing backfiles have expanded the assignment of DOIs to items that predate the DOI system.

The earliest article assigned a DOI is "An Accompt of the Improvement of Optick Glasses" published in 1665 in the first issue of Philosophical Transactions (Royal Society of London for Improving Natural Knowledge) Note: This is a permalink. Because the article is a library subscription (licensed  resource) this link will not open the article if you are off campus. Note: this link is formatted as a library EZProxy link. You can login to your UD account to access the article. (Works both on and off campus.)

EZProxy: How to Create a Permalink to UD Library Licensed eResources

Off campus users will find that a permalink is a dead end when it links to a library licensed resource.

The solution is to use the EZproxy URL Link Creator to create a UD authenticated permalink. Use when you are sending URLs to off campus users, including distance learners. For more information, see the Research Guide: Permalinks.


Digital Object Identifier (DOI)

A DOI is an alphanumeric name that identifies digital content, such as a journal article, a book, or a chapter in a book. This differs from a URL, which identifies a location on the web. A DOI is a permanent identifier; if the URL changes, the DOI will still identify and locate the item.

A DOI begins with the number 10; e.g., 10.1177/1362361315607724

The DOI identifies but it does not retrieve.

Note: DOIs are not assigned to magazine or newspaper articles.

Where Are DOIs?

DOIs can be found in one or more of these places:

First page of an article


Article description in a database


Article information on publisher webpage

Note: (the DOI is being used as a link; this is a permalink.)


Subject Guide

Rebecca Knight's picture
Rebecca Knight
Associate librarian
Reference and Instructional Services Department
Morris Library, Room 117H

Subjects: U.S. Government Information,
Delaware, census, family studies, RefWorks, APA style, and genealogy.

B.A., History. University of North Carolina, Chapel Hill. 1973.
M.S., Library Science. University of North Carolina, Chapel Hill. 1981.



RefWorks: How Can It Help You?

RefWorks is a web-based citation management system. The system can:

  • export references from databases
  • organize references
  • store articles
  • supply space and tools to add notes about the references and articles
  • share folders
  • format citations and references lists in hundreds of citation styles
  • insert properly formatted in-text citations (or footnotes) and references lists (or bibliographies or works cited lists) when using Microsoft Word or Google Docs

DOIs, Permalinks, & UD Library EZproxy Permalinks