Ming Hua Jian Pei Wenjie Zhang Xuemin Lin Efficiently Answering Probabilistic Threshold Top-k Queries on Uncertain Data. 1403-1405 2008 ICDE http://dx.doi.org/10.1109/ICDE.2008.4497570 conf/icde/2008 db/conf/icde/icde2008.html#HuaPZL08