Stefan Berghofer Markus Wenzel Inductive Datatypes in HOL - Lessons Learned in Formal-Logic Engineering. 19-36 1999 conf/tphol/1999 TPHOLs http://link.springer.de/link/service/series/0558/bibs/1690/16900019.htm db/conf/tphol/tphol99.html#BerghoferW99