Zhexue Huang Per Svensson Hans Hauska Solving Spatial Analysis Problems with GeoSAL, A Spatial Query Language. 1-17 SSDBM92/P001.pdf 1992 SSDBM db/conf/ssdbm/ssdbm92.html#HuangSH92 conf/ssdbm/92 db/conf/ssdbm/HuangSH92.html