Arturas Mazeika Michael H. Böhlen Peer Mylov Using Nested Surfaces for Visual Detection of Structures in Databases. 91-102 2008 Visual Data Mining http://dx.doi.org/10.1007/978-3-540-71080-6_7 series/lncs/4404 db/series/lncs/lncs4404.html#MazeikaBM08