Weiland, Ulrike. “Planning Cycle for a Sustainable Development of Urban Regions”. Raumforschung und Raumordnung | Spatial Research and Planning 59, no. 5-6 (September 30, 2001): 392–401. Accessed May 5, 2024. https://rur.oekom.de/index.php/rur/article/view/1507.