Hoyler, Michael. “External Relations of German Cities Through Intra-Firm Networks—A Global Perspective”. Raumforschung und Raumordnung | Spatial Research and Planning 69, no. 3 (June 30, 2011): 147–159. Accessed July 15, 2024. https://rur.oekom.de/index.php/rur/article/view/785.