db/conf/gis/WilschutZFBQ98.html Annita N. Wilschut Roelof van Zwol Jan Flokstra Nick Brasa Wilko Quak Road Collapse in Magnum. 20-27 GIS1998/P020.pdf 1998 conf/gis/98 ACM-GIS http://doi.acm.org/10.1145/288692.288698 db/conf/gis/gis98.html#WilschutZFBQ98