Sven-Erik Bornscheuer Michael Thielscher Explicit and Implicit Indeterminism: Reasoning About Uncertain and Contradictory Specifications of Dynamic Systems. 119-155 1997 31 J. Log. Program. 1-3 db/journals/jlp/jlp31.html#BornscheuerT97 http://dx.doi.org/10.1016/S0743-1066(96)00124-0