Gereon Frahling Piotr Indyk Christian Sohler Sampling in Dynamic Data Streams and Applications. 3-28 2008 18 Int. J. Comput. Geometry Appl. 1/2 http://dx.doi.org/10.1142/S0218195908002520 db/journals/ijcga/ijcga18.html#FrahlingIS08