Representing Nested Inductive Types Using W-Types.

Michael Abbott Thorsten Altenkirch Neil Ghani Representing Nested Inductive Types Using W-Types. 59-71 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3142&spage=59 2004 conf/icalp/2004 ICALP db/conf/icalp/icalp2004.html#AbbottAG04