Buhmann, E., Wiesel, J. (2004). GIS Report [online]. B. Harzer Verlag, Karlsruhe. Available from: http://www-bbg.hrz.hs-anhalt.de/gis/ [Accessed 16 January 2005]. Exhaustive, unfortunately infrequently updated overview of GIS software and add-ons including technical informatioe etc. German.