William Perrizo Qin Ding Qiang Ding Amalendu Roy Deriving High Confidence Rules from Spatial Data Using Peano Count Trees. 91-102 2001 conf/waim/2001 WAIM http://link.springer.de/link/service/series/0558/bibs/2118/21180091.htm db/conf/waim/waim2001.html#PerrizoDDR01