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Date: Wed 13 Feb 2019

This week we learn about interoperability and link resolvers. Link resolvers are a technical solution to help users of electronic resources access the full text of a citation in a library's collections, or to acquire access through some other means, such as through interlibrary loan or through identifying the location of the work on the library shelf. In particular, the technology is a way to provide access to a library's collections from a browser even if the user is not specifically searching within the library's website, or more specifically, within its discovery system. If it helps, link resolvers are simply a way to search across multiple systems at one, just like you or I would do in a federated search discovery system.

Let's imagine that you have conducted a search in Google Scholar, let's call this the source, and you have identified an article that you wish to retrieve. If you have made Google Scholar aware that you are affiliated with a specific library and if that library uses a link resolver service, then:

  1. the metadata about the article will be extracted from the source, in this case, that's Google Scholar, and this will be added to
  2. the metadata about the institution (administrative metadata, such as an institutional ID number).
  3. the metadata is converted into a URL query that queries the library's collections
  4. the user is then presented with target options (or taken directly to the work) for retrieving the article, and the options may include full text access from various and possibly multiple vendors or publishers, information about the physical location (e.g., on the shelves) if it exists, or options to request the work through interlibrary loan. Ideally, it will lead the user directly to the full text.

See Link Resolver 101 for additional details and this historical piece on link resolvers.

Let's consider a basic keyword search on Google Scholar for the term [ knowledge management ]. One of the first items listed in the results page is to an article titled "A systems thinking framework for knowledge management." If you've already gone to Google Scholar's settings, and added your library to the Library Links list, then you should see a View Now @ UK link off to the right of your searches there. This indicates the likelihood, although there could be an error, that the article is available through UK Libraries.

Now we take a look at the URL for the View Now @ UK link by right clicking on it and breaking it down into its components. What we see here is what is called a query string. A query string is a part of the URL that contains (metadata) fields and values for those fields, and it begins after the letter q in the URL. Each new parameter, or field, begins after each ampersand. In the query below, I start each newline with a new field and end it with its value:

Most of what we see in that URL is meaningless to us because it's metadata specific to Google's protocols, but if we click on that View Now @ UK link, we are now transported, because of the information in the previous link, to UK's discovery service, Primo, by Ex Libris.

In Primo, if we look at the new URL, we see specifically that it's an OpenURL link and we can see the fields and values and identify the metadata (one line is broken up for readability). The percent signs and numbers in the title field are called Percent-encoding, and are used to convert characters that are URL unfriendly, like empty spaces between words, to something that URLs can handle and parse. See this page for a table of UTF-8 percent-encodings and the characters they match:

Also, the resulting page is the menu of options available to us to gain access to the work. The link resolver technology works and translates the metadata as needed for the appropriate service. If I click on the ILL link, then the URL becomes this, which will be used to complete a ILL form (one line is broken up for readability):

This all works because the various publishers and vendors, and their associated applications, have agreed to using this technology.

Now let's thus consider an example of a database that a library subscribes to, such as EBCOHost's Academic Search Complete. Here again I search for the term [ knowledge management ]. Academic Search Complete is more than a bibliographic database, it also provides access to full text articles within its own database (Google Scholar will link to them if they're freely available on the web, but it doesn't actually collect them). However, ASC also provides access to bibliographic records to items that it does not provide full text access to. This is where the link resolver comes into play.

For those bibliographic records that are not available as full text in ASC, the link resolver used by UK Libraries will be displayed underneath the record in the ASC results or even after clicking on the full display of the record. Here you see the link resolver in action in the form of the View Now @ UK button. Clicking on that will open the link resolver menu, and we will see a list of options for accessing the full text of the article. If the article is available full text somewhere in the library, such as through a different database, we should see that here, but if not, there should be options for requesting the item through interlibrary loan, as well as options for accessing the item in the library's physical collections if it exists there.

Our readings this week by Kasprowski (2012) and by Chisari et al. (2017) discuss in some ways how the link resolver technology works and how to evaluate link resolver technology. It may not be necessary to learn how to hack your way through the OpenURL syntax or other aspects of link resolver URL formatting, but it is a good idea to have at least a basic understanding how the URLs work in this process.

Let me highlight that the key way that link resolvers work is by embedding citation metadata within the link resolver URL, including administrative metadata. Thus, as you guessed it, this is another reason why it's important to have high quality metadata for our records, as our readings note, and thus, by implication, if we find that link resolvers break down, it might be that the metadata is incorrect or has changed in some important way.

For this week, I'll provide a link to the some documentation about the link resolver technology used by UK Libraries use of ExLibres Alma. Let's discuss this documentation in this week's forum. I also want you to find and explain other instances of link resolvers. Be sure to provide links to these examples and perhaps point out some ways the technology can be evaluated.

Documentation to read and discuss:

Additional information:

teaching/interoperability.txt · Last modified: 2019/02/08 21:02 by seanburns