Hyun-Jeong Seok Gang Qian Qiang Zhu Alexander R. Oswald Sakti Pramanik Bulk-Loading the ND-Tree in Non-ordered Discrete Data Spaces. 156-171 2008 DASFAA http://dx.doi.org/10.1007/978-3-540-78568-2_14 conf/dasfaa/2008 db/conf/dasfaa/dasfaa2008.html#SeokQZOP08