Ferdinando Di Martino Salvatore Sessa Spatial Analysis with a Tool GIS via Systems of Fuzzy Relation Equations. 15-30 2011 ICCSA (2) http://dx.doi.org/10.1007/978-3-642-21887-3_2 conf/iccsa/2011-2 db/conf/iccsa/iccsa2011-2.html#MartinoS11