db/conf/gis/NittelYM96.html Silvia Nittel Jiong Yang Richard R. Muntz Mapping a Common Geoscientific Object Model to Heterogeneous Spatial Data Repositories. 50-57 GIS1996/P050.pdf 1996 conf/gis/96 ACM-GIS http://doi.acm.org/10.1145/258319.258335 db/conf/gis/gis96.html#NittelYM96