full text database studies?

[Sigrid E Kelsey]

I am interested in any non-biased, in-depth, recent studies comparing
EBSCO: Academic Search Elite, ProQuest Research Library Core, and Infotrac
Expanded Academic.  Has anyone conducted any studies you would be willing
to share with me?  I'm interested in relevancy studies, subject-area
coverage, etc.  The most recent I found in the Web4lib archives is 1997.

thanks,
Sigrid Kelsey
Louisiana State University