Manfred Broy Ursula Hinkel Tobias Nipkow Christian Prehofer Birgit Schieder Interpreter Verification for a Functional Language. 77-88 1994 conf/fsttcs/1994 FSTTCS db/conf/fsttcs/fsttcs94.html#BroyHNPS94 http://dx.doi.org/10.1007/3-540-58715-2_115