Francesco M. Malvestuto Mauro Mezzini Marina Moscarini Auditing sum-queries to make a statistical database secure. 31-60 2006 9 ACM Trans. Inf. Syst. Secur. 1 http://doi.acm.org/10.1145/1127345.1127347 db/journals/tissec/tissec9.html#MalvestutoMM06