Peter C. Lockemann Alfons Kemper Guido Moerkotte Future Database Technology: Driving Forces and Directions. 15-33 1990 conf/ibm/1990 IBM Symposium: Database Systems of the 90s db/conf/ibm/db90.html#LockemannKM90 http://dx.doi.org/10.1007/3-540-53397-4_30