Topological Relations Between Regions in R² and Z².

http://dx.doi.org/10.1007/3-540-56869-7_18 Max J. Egenhofer Jayant Sharma Topological Relations Between Regions in R² and Z². 316-336 SSD/1993/P316.pdf 1993 conf/ssd/93 SSD db/conf/ssd/ssd93.html#EgenhoferS93