db/conf/gis/PapadiasD97.html Dimitris Papadias Vasilis Delis Relation-Based Similarity. 1-4 GIS1997/P001.pdf 1997 conf/gis/97 ACM-GIS http://doi.acm.org/10.1145/267825.267830 db/conf/gis/gis97.html#PapadiasD97