Hüppauff, Jakob. “Safeguarding Agricultural Land in Spatial planning – Results of a nationwide Plan Content Analysis”. Raumforschung und Raumordnung | Spatial Research and Planning 84, no. 2 (April 30, 2026): 84–102. Accessed August 15, 2026. https://rur.oekom.de/index.php/rur/article/view/3365.