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Tutorial: Permanent Links to Online Documents: Using a DOI


Create a DOI Link

To create a permanent link using a DOI, copy and paste the following at the beginning of your DOI:

This creates a direct link with off-campus access through the Trent Library.  Test the link to be sure it works for you.

Use a DOI

  1. Most of the time Omni can find an item with the DOI - just enter it into the search box. If it isn't found in "Trent Library", broaden your search to "Add results beyond Trent's collection".
  2. You can also click the following link and enter your DOI into the search box:
  3. Google is also excellent at locating a document by DOI; just enter the DOI and search. Better yet, use Google Scholar with the Trent Library links activated and you don't need to worry about the proxy from off-campus. See how.

Trent Specifics

  • The proxy server prefix is essential to ensure off-campus access to resources procured by the Trent Library. 
    • Always use the proxy prefix for a restricted-access document provided by the Library.
    • Never use the proxy prefix if it's a public document freely available to anyone.
  • A DOI links to a specific location.  If Trent doesn't subscribe to the journal at that location, you won't have access - try another route to see if we subscribe from another site. 

Helpful Links

What is a DOI?

A unique alphanumeric string assigned to a digital object – in this case, an electronic journal article or a book chapter. In the CrossRef system, each DOI ... uniquely identifies the content item and provides a persistent link to its location on the internet.
(from CrossRef. CrossRef is the official DOI registration agency for scholarly and professional publications.)

The Digital Object Identifier (DOI®) System is for identifying content objects in the digital environment. DOI® names are assigned to any entity for use on digital networks. They are used to provide current information, including where they (or information about them) can be found on the Internet. Information about a digital object may change over time, including where to find it, but its DOI name will not change"

A DOI is the standard for identifying online locations of items such as journal articles. It is a unique number to identify a specific online item. The DOI has recently been added to APA guidelines as a requirement for citing material. It is a truly persistent link that is always reliable.

More information is available at the CrossRef website, where you can also watch a Flash presentation demonstrating DOIs.

The Anatomy of a DOI

A DOI has a prefix, a slash, and a suffix. To understand how it's designed, let's use an example:

The DOI for an article entitled "Atomic Force Microscopy of Cholera Toxin B-oligomers Bound to Bilayers of Biologically Relevant Lipids" in the Elsevier journal Journal of Molecular Biology is:


image of a doi: 10.1006/jmbi.1995.0238

DOI Prefix

In scholarly publications, the DOI begins with a prefix of 10.XXXX.

  • Each prefix is assigned to a specific publisher.
  • It always starts with 10, then a period, then 4 numbers.
  • Each publisher has a unique 4-number prefix.
  • In our example, the publisher is Elsevier and Elsevier's prefix is 10.1006.

DOI Suffix

A suffix is assigned by the publisher and can take any form the publisher chooses.

  • The suffix refers to a particular item available from that publisher.
    • In this case it refers to a specific article.
  • Elsevier has assigned the letters "jmbi" to the Journal of Molecular Biology. They developed their own code to identify each article within that journal.

Creating a Link to a DOI

If you want to create a link to an article, book, or other object using a DOI, it needs a full address; just the DOI isn't enough.

  • The address (url) must go to the DOI website, which decodes it and directs the user to the correct location. 
  • This is called "resolving the url".

The website is at


Two Methods

Create a DOI link to a document, using one of two methods:

  1. Go to the DOI website and enter a DOI in the box, which will re-direct you to the correct location.  OR
  2. Add the website url to the beginning of your DOI.
    • doi: jmbi.1995.0238
    • url:
    • This goes to the DOI website, resolves the url, and sends you to the correct location - seamlessly. You won't see this happening; you'll just land on the site of the document.

Trent Specifics

If the document has restricted access and the Trent Library provides this access, the proxy server prefix is needed for off-campus authentication:



To give Trent users access to an item from off-campus, the full link to our example would be

See more information about the proxy server under the "Authentication" tab.

Trent Authentication

If the document has restricted access AND the Trent Library provides this access, the proxy server prefix is needed for off-campus authentication.

The proxy prefix for Trent is:

To give Trent users access to an item from off-campus, the full link to our example would be

Keep in Mind:

  • Because the proxy server is of no use to those outside of Trent, it should only be used for Trent communications, such as course readings and assignments marked by Trent instructors.
  • If the document is not restricted (i.e. it's a free site), DO NOT use the proxy prefix.  It won't work.
  • If the document is not subscribed to by the Trent Library, DO NOT use the proxy prefix.  It won't work.

Finding a DOI for a Document

APA guidelines include a requirement for a DOI for online references. There are aids to help you find a DOI if you don't already know it. CrossRef offers some options:

Simple Text Query This form allows you to retrieve Digital Object Identifiers (DOIs) for journal articles, books, and chapters by cutting and pasting the reference list into the box. The form searches for DOI matches for your citations.
Guest Query Form This is a more structured form that allows you to submit bibliographic information (such as title, author, journal title, ISBN, etc). The form searches for DOI matches for your data. If the simple text query fails, this one may work better.


There's a 3-minute video from APA showing DOI retrieval from the PsycINFO database on YouTube.

For information on using a DOI in APA style referencing, see the Publication Manual of the American Psychological Association (6th ed.) which is available from Reserve or in the Reference section at BF 76.7 .A46 2010.

A DOI links to a specific home for a digital document, and it may not be accessible to everyone on that site; often there's a paywall.

The easiest way to search for an item by DOI is to enter it into Omni. If we have access to it, Omni will find it. If you're signed into Omni, you'll have access.