Johannes Gehrke Flip Korn Divesh Srivastava On Computing Correlated Aggregates Over Continual Data Streams. 13-24 2001 SIGMOD Conference db/conf/sigmod/sigmod2001.html#GehrkeKS01 http://doi.acm.org/10.1145/375663.375665 http://www.acm.org/sigs/sigmod/sigmod01/eproceedings/papers/Research-Gehrke-et-al.pdf