Deepak Chawla Lin Li Stephen Scott Efficiently Approximating Weighted Sums with Exponentially Many Terms. 82-98 2001 conf/colt/2001 COLT/EuroCOLT http://link.springer.de/link/service/series/0558/bibs/2111/21110082.htm db/conf/colt/colt2001.html#ChawlaLS01