src/HOL/Library/Product_ord.thy
2007-01-25 haftmann 2007-01-25 improved
2006-11-22 haftmann 2006-11-22 added code lemmas
2006-05-27 wenzelm 2006-05-27 tuned;
2005-08-31 wenzelm 2005-08-31 tuned presentation;
2005-04-15 nipkow 2005-04-15 New