@techreport{R-94-45,
YEAR = {1994},
NUMBER = {R-94-45},
INSTITUTION = ida,
ADDRESS = idaaddr,
ABSTRACT = {},
IDANR = {LiTH-IDA-R-94-45},
AUTHOR = {Laurent Fribourg, Hans Olsén},
TITLE = {Direct,
		 Dual and Contrapositive Proofs by Induction.},
NOTE = {Accepted
		 to LOPSTR 94 (Preproceedings), Pisa, Italy, June
		 1994.}