Linking to Articles

Creating Persistent URLs (PURLs)

What are persistent links?

Persistent links, also called durable links, are internet addresses or URLs (Uniform Resource Locators) that remain consistent and do not change over time. For example, our library home page can always be reliably reached at http://www.calstatela.edu/ library. It is a persistent or durable link and has a PURL (Persistent URL). However, a link to an article in one of the library’s databases could change each time you try to access it (unless you know how to reconfigure it), because databases often create their links at the moment you access them.

NOTE: Not all of the library’s databases and electronic journals offer the ability to deep-link directly to an article or item of information.

Why should I use persistent links?

Having a persistent link to an item such as a full text article located within a database allows you to share the link to the article with the knowledge that the link will work later and not end up in a frustrating dead-end for the person(s) to whom you provided it.

Faculty or students might wish to provide a link to an article within WebCT or Library reserves, on a web page, in a Power Point presentation, on a hyperlinked Microsoft Word document, or in an email.

Students may be asked by their professors to add persistent links to bibliographies whenever eJournals are cited. This, in turn, allows the professor easy access to examine the references cited by students in term papers.

Remember, access to most library full-text databases are limited to CSULA faculty, students and staff by licensing agreements and copyright guidelines.

Keep copyright rules in mind when linking or downloading library materials.

  • U.S. Copyright law (Title 18, US Code) applies to items you might wish to place in your WebCT course or on a web page. In addition, each database or eJournal vendor has its own specific information regarding licensing restrictions and you should review these terms and conditions to see if what you want to do is allowed.
  • Copyright also requires that you include the completed citation information with your links. The text of your link should include author, title, publication, volume and issue number (if applicable), copyright year and page numbers. As stated before, this information is also helpful to have should a link expire and you or your students need to locate the article again.

How do I create a persistent link?

Persistent links for resources accessed via CSULA Library collections consist of two parts. One is the address for the item desired and the other is a proxy script (http://mimas.calstatela.edu/login?url=). The proxy script points the address to the library’s proxy server and allows CSULA community members to authenticate and use the resource from off-campus. Here is a sample showing how you would put the proxy script in front of the PURL that you copied from your source.

PURL for article:
McCarthy, Michael. Economics of obesity. Lancet 364 (9452): 2169.

http://search.epnet.com/login.aspx?direct=true&db=aph&an=15397386
This link will work from all computers on campus.

CSULA proxy script plus PURL for article:
McCarthy, Michael. Economics of obesity. Lancet 364 (9452): 2169.

http://mimas.calstatela.edu/login?url=http://search.epnet.com/login.aspx?direct=true&db=aph&an=15397386
This link will work from on- and off-campus computers with proper campus NIS authentication.

NOTE: Persistent links are usually just that, persistent, and not permanent. As a result it is best to test them regularly and include the citation and the name of the database or eResource within which the article or item is located.

After creating the PURLs, make sure to test the link from on- and off-campus. Retest every few months, as necessary, to verify that the link still persists and has not become obsolete.

Faculty, make sure your students have, and know how to use, their CSULA NIS username and password. Explain how NIS accounts are used to provide authenticated access to subscription library resources.

Need help creating a persistent link?

Contact Holly Yu at hyu3@calstatela.edu for assistance.