Stefan Berghofer Makarius Wenzel Logic-Free Reasoning in Isabelle/Isar. 355-369 2008 AISC/MKM/Calculemus http://dx.doi.org/10.1007/978-3-540-85110-3_31 conf/aisc/2008 db/conf/aisc/aisc2008.html#BerghoferW08