Yasunori Ishihara Shuichiro Ako Toru Fujiwara Security against Inference Attacks on Negative Information in Object-Oriented Databases. 49-60 2002 conf/icics/2002 ICICS http://link.springer.de/link/service/series/0558/bibs/2513/25130049.htm db/conf/icics/icics2002.html#IshiharaAF02