Database and Expert Systems Applications 18th International Conference, DEXA 2007, Regensburg, Germany, September 3-7, 2007: Proceedings - International Workshop on Database and Expert Systems Applications 2007 : Regensburg, Germany); Wagner, Roland; Pernul, Gunther; Revell, Norman; SpringerLink (Online service) (Berlin, Heidelberg : Springer-Verlag Berlin Heidelberg, 2007)