Flacke, Johannes. “Sustainability and GIS: Spatially Differentiated Sustainability Indicators in Municipal Information Systems for Promotion of a Sustainable Settlement Development”. Raumforschung und Raumordnung | Spatial Research and Planning 61, no. 3 (March 31, 2003): 150–159. Accessed August 15, 2026. https://rur.oekom.de/index.php/rur/article/view/1615.