Since April 2004, all preprints authored or co-authored by Dr. Hughes have appeared as Oden Institue (formerly ICES) Research Reports in downloadable pdf format. Go to
http://www.oden.utexas.edu/research/reports/
and search by entering "Hughes”. Most preprints are eventually published as journal or book articles and frequently undergo substantial revisions before appearing in final form. The Oden Institute reports are not updated to reflect that. The best source of information is always the final published version.