title: on the issue of valid time ( s ) in temporal databases. authors: s kokkotos , e ioannidis , t panayiotopoulos , c spyropoulos. venue: sigmod record. year: 1995
title: on the issue of valid time ( s ) in temporal databases. authors: s kokkotos , ev ioannidis , t panayiotopoulos , cd. venue: sigmod record ,. year: 1995.0