%0 Journal Article %J J. Comput. Syst. Sci. %D 2001 %T Semantics and Expressive Power of Nondeterministic Constructs in Deductive Databases %A Fosca Giannotti %A Dino Pedreschi %A Carlo Zaniolo %B J. Comput. Syst. Sci. %V 62 %P 15-42 %G eng