http://doi.acm.org/10.1145/381854.381879 db/journals/sigmod/SonDT96.html Sang Hyuk Son Rasikan David Bhavani M. Thuraisingham Improving Timeliness in Real-Time Secure Database Systems. 29-33 sigmodR/25-1/P029.pdf 1996 25 SIGMOD Record 1 db/journals/sigmod/sigmod25.html#SonDT96 http://www.acm.org/sigmod/record/issues/9603/real7.ps