Mike Bergman has a comprehensive list of about 100 papers on Wikipedia as a knowledge source.
“Since about 2005 â€” and at an accelerating pace â€” Wikipedia has emerged as the leading online knowledge base for conducting semantic Web and related research. The system is being tapped for both data and structure. Wikipedia has arguably replaced WordNet as the leading lexicon for concepts and relations. Because of its scope and popularity, many argue that Wikipedia is emerging as the de facto structure for classifying and organizing knowledge in the 21st century.”
This complements a similar list on Wikipedia itself, Wikipedia in academic studies.
“Below is an incomplete list of academic conference presentations, peer-reviewed papers and other types of academic writing which focus on Wikipedia as their subject. Works that mention Wikipedia only in passing are unlikely to be listed. Unpublished works of presumably academic quality are listed in a dedicated section.”
(spotted on the dbpedia mailing list)