Constructing Polymorphic Programs with Quotient Types.

Michael Abbott Thorsten Altenkirch Neil Ghani Conor McBride Constructing Polymorphic Programs with Quotient Types. 2-15 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3125&spage=2 2004 conf/mpc/2004 MPC db/conf/mpc/mpc2004.html#AbbottAGM04