@book{Preston2011, author = {Preston, Richard E.}, year = {2011}, language = {eng}, copyright = {http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen}, title = {Walter Christaller’s research on regional and rural development planning during World War II}, url = "http://dx.doi.org/10.17169/refubium-22138", }