CT-1994-08: Apt, Krzysztof R. and van Emde Boas, Peter and Welling, Angelo (1994) The STO-problem is NP-hard. [Report]
CT-1993-06: Apt, Krzysztof R. (1993) Declarative programming in Prolog. [Report]
CT-1992-03: Apt, Krzysztof R. and Doets, Kees (1992) A new Definition of SLDNF-resolution. [Report]
CT-1991-12: Apt, Krzysztof R. and Pedreschi, Dino (1991) Reasoning about Termination of Prolog Programs. [Report]