Deepak Ajwani Khaled M. Elbassioni Sathish Govindarajan Saurabh Ray Conflict-free coloring for rectangle ranges using <i>O</i>(<i>n</i><sup>.382</sup>) colors. 181-187 2007 conf/spaa/2007 SPAA http://doi.acm.org/10.1145/1248377.1248406 db/conf/spaa/spaa2007.html#AjwaniEGR07