Ira Assent Andrea Wenning Thomas Seidl Approximation Techniques for Indexing the Earth Mover's Distance in Multimedia Databases. 11 2006 conf/icde/2006 ICDE http://doi.ieeecomputersociety.org/10.1109/ICDE.2006.25 db/conf/icde/icde2006.html#AssentWS06