Hung Son Nguyen Andrzej Skowron Marcin S. Szczuka Situation Identification by Unmanned Aerial Vehicle. 49-56 2000 conf/rsctc/2000 Rough Sets and Current Trends in Computing http://link.springer.de/link/service/series/0558/bibs/2005/20050049.htm db/conf/rsctc/rsctc2000.html#NguyenSS00