Ivan Kramosil Boolean-like and frequentistic nonstandard semantics for first-order predicate calculus without functions. 45-57 2001 5 Soft Comput. 1 http://www.springerlink.com/openurl.asp?genre=article&issn=1432-7643&volume=5&issue=1&spage=45 db/journals/soco/soco5.html#Kramosil01