Kenneth A. Ross Divesh Srivastava Peter J. Stuckey S. Sudarshan 0001 Foundations of Aggregation Constraints. 193-204 1994 conf/ppcp/1994 PPCP db/conf/ppcp/ppcp94-lncs.html#RossSSS94 http://dx.doi.org/10.1007/3-540-58601-6_101