Shivanand Balram Suzana Dragicevic Modeling Collaborative GIS Processes Using Soft Systems Theory, UML and Object Oriented Design. 199-218 2006 10 T. GIS 2 http://dx.doi.org/10.1111/j.1467-9671.2006.00253.x db/journals/tgis/tgis10.html#BalramD06