conf/pods/87 Francesco M. Malvestuto Answering Queries in Categorial Data Bases. 87-96 1987 PODS db/conf/pods/pods87.html#Malvestuto87 http://doi.acm.org/10.1145/28659.28668 db/conf/pods/Malvestuto87.html journals/anthology/cd1-3:PODS87/P087.PDF journals/anthology/dvd1:text/1-3/PODS87/P087.PDF ... journals/jacm/BeeriFMY83 ... ... ... ... ... ... ... ... ... ... ... journals/is/Malvestuto86 ... conf/icdt/Malvestuto86 ... journals/tse/ShoshaniW85