Frank Atanassow Johan Jeuring Inferring Type Isomorphisms Generically. 32-53 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3125&spage=32 2004 conf/mpc/2004 MPC db/conf/mpc/mpc2004.html#AtanassowJ04