We've been experimenting a lot today with this outstanding xrefer research tool from the UK. Looks like the full featured version is only available to libraries and institutions but the material I have been finding and exploring is outstanding. The cross reference features, embedded hyperlinks, and relatedness of the taxonomy are very powerful. I can't put a table with the search button here in the body of the weblog foir some reason (must conflict with blogger's css template), but I have put it in a box to the left. Look for this logo:

They have combined aand interlinked about 100-120 reference titles from several top UK publishers. Check it out.

The material below from the famous Oxford Dictionary of Art came from this tool and I have restored the embedded hyperlnks plus added a few extras as an experiment.