@InCollection{PfeiferRuess:WGP98,
    author    = "H. Pfeifer and H. Rue{\ss}",
    title     = "{Polytypic Abstraction in Type Theory}",
    booktitle = "Workshop on Generic Programming (WGP'98)",
    location  = "Marstrand, Sweden",
    month     = "June",
    publisher = "Dept.\ of Computing Science, Chalmers Univ.\ of Technology,
		 and G{\"o}teborg Univ.", 
    editor    = "Roland Backhouse and Tim Sheard",
    url       = "http://www.cs.uu.nl/people/johanj/programme_wgp98.html",
    year      = "1998"
}