title: containment of conjunctive queries : beyond relations as sets. authors: raghu ramakrishnan , yannis e. ioannidis. venue: acm trans . database syst .. year: 1995.0
title: containment of conjunctive queries : beyond relations as sets. authors: yannis e. ioannidis , raghu ramakrishnan. venue: acm transactions on database systems ( tods ). year: 1995.0