Advances in Databases and Information Systems : Associated Workshops and Doctoral Consortium of the 13th East European Conference, ADBIS 2009, Riga, Lativia, September 7-10, 2009. Revised Selected Papers - Janis Grundspenkis, Marite Kirikova, Yannis Manolopoulos, Leonids Novickis ((Lecture Notes in Computer Science))