title: on the semantics of `` now '' in databases. authors: christian s. jensen , tomás isakowitz , richard t. snodgrass , curtis e. dyreson , james clifford. venue: acm trans . database syst .. year: 1997
title: on the semantics of now in databases. authors: james clifford , curtis dyreson , tom &#225; s isakowitz , christian s. jensen , richard thomas snodgrass. venue: acm transactions on database systems ( tods ). year: 1997