Laggner, Birgit, Natascha Orthen, Bernhard Osterburg, and Norbert Röder. “Is the Increasing Bio-Methane Production the Sole Reason for the Declining Grassland Area in Germany? An Analysis of Geo-Referenced Land Use Data”. Raumforschung und Raumordnung | Spatial Research and Planning 72, no. 3 (June 30, 2014): 195–209. Accessed August 25, 2026. https://rur.oekom.de/index.php/rur/article/view/627.