Reference materials – there are many different software tools out there that can provide linked web pages. In fact, you are currently using one of the commonest, the simple web site. WordPress, and other content management systems, do a very nice job of providing easily linkable resources.
Wikis are another very simple and easily editable set of connected pages. In our cases, we use TiddlyWiki, a lovely little single file wiki system that is all self-contained, to provide wiki features within our OpenLabyrinth cases.
But the big advantage that OpenLabyrinth provides is that it tracks what the user does in great detail. Every click, choice, response to a question, branch in a pathway, is captured in the underlying database, along with precise timestamps of when it happened.
This activity tracking provides great power in assessing what your learners do, how your cases perform, or how your teachers facilitate. This is particulary useful for reference materials because you can then tune your resources to adapt to their usage and what your users need.