Using Persistent Links (PURLs)
- What is a PURL?
- How do I obtain a PURL?
- Why do I want to use a PURL?
- What does a PURL look like?
- How do I create a PURL using a DOI?
- Best practices of using a PURL
Persistent URLs or PURLs are durable links that connect users directly to an article, e-book, or other items in our proprietary library electronic resources. PURLs are also known as persistent links, stable URLs, or stable links.
As a general rule if you want to save a link to an article for future use, do not cut and paste the link from the browser's address bar - it may not work over time.
Rather, you want to look for a persistent URL (PURL). This is a URL that you can always use to link back to an article. For example, it may say something like Persistent link, Document URL, or Stable URL. Of course there are always exceptions to every rule. If you have trouble finding a PURL please do not hesitate to Ask a Librarian. We are here to help!
- PURLs can be useful when creating syllabus, online reading lists or bibliographies and other research tools.
- PURLs help instructors remain in compliance with copyright rules when linking to articles rather than copying the articles themselves and making it available through WebTycho and other teaching media.
- Linking to search objects provides the UMUC Library with more consistent usage statistics for our databases.
A PURL looks just like a URL because it is a URL. PURLs for resources available at UMUC consists of two parts. The first part is the proxy script (http://ezproxy.umuc.edu/login?url=) followed by the search object’s address. The proxy script connects to the proxy server and authenticates UMUC users to use the resource from off-campus. Below is a sample of a PURL with its two parts.
There are exceptions. Sometimes the proxy script is included within the PURL. If you do not see our proxy script, you always need to be sure to include the UMUC proxy as a prefix in a PURL (http://ezproxy.umuc.edu/login?url=) from our electronic resources, as shown in the example above.
A digital object identifier (DOI) is a permanent digital identifier given to an object. Its most common application is identifying electronic documents. In the database record for an article, you will see an element that looks like this:
More and more databases provide DOIs as opposed to URLs. The process of generating a persistent link for those databases is a little different. In addition to the Library proxy prefix, another URL (http://dx.doi.org/) has to be added in order to provide access. Here is an example of a persistent link using a DOI.
- Links are usually persistent but NOT necessarily permanent. PURLs may become obsolete over time. Make sure to test the links on a semester basis.
- Copyright rules are no exceptions for PURLs. Make sure to cite the search object and source when linking or downloading library materials.
- Not all databases vendors offer PURLs. Consider first limiting your searches to the databases that can be accessed with a PURL if that suits your needs.