Nassima Djafri Alvaro A. A. Fernandes Norman W. Paton Tony Griffiths Spatio-temporal evolution: querying patterns of change in databases. 35-41 2002 conf/gis/2002 ACM-GIS http://doi.acm.org/10.1145/585147.585156 db/conf/gis/gis2002.html#DjafriFPG02