Ferdinando Di Martino Vincenzo Loia Salvatore Sessa Extended fuzzy C-means clustering algorithm for hotspot events in spatial analysis. 31-44 2008 5 Int. J. Hybrid Intell. Syst. 1 http://iospress.metapress.com/openurl.asp?genre=article&issn=1448-5869&volume=5&issue=1&spage=31 db/journals/ijhis/ijhis5.html#MartinoLS08