Haim Kaplan Natan Rubin Micha Sharir Elad Verbin Efficient Colored Orthogonal Range Counting. 982-1011 2008 38 SIAM J. Comput. 3 http://dx.doi.org/10.1137/070684483 db/journals/siamcomp/siamcomp38.html#KaplanRSV08