Werner Stephan Bruno Langenstein Andreas Nonnengart Georg Rock Verification Support Environment. 476-493 2005 conf/birthday/2005siekmann Mechanizing Mathematical Reasoning http://springerlink.metapress.com/openurl.asp?genre=article&id=RYV43ABAAGF6L2BV db/conf/birthday/siekmann2005.html#StephanLNR05