@conference {DBLP:conf/fqas/GiannottiMNP98, title = {Query Answering in Nondeterministic, Nonmonotonic Logic Databases}, booktitle = {FQAS}, year = {1998}, pages = {175-187}, author = {Fosca Giannotti and Giuseppe Manco and Mirco Nanni and Dino Pedreschi} }