Schou., Axel. “Freeman, Olis W. & Raup, H. F.: Essentials of Geography. 48X25 Cm, 487 s., 262 Fig. Mc. Graw-Hill Series in Geography. New York, Toronto, London 1949”. Geografisk Tidsskrift - Danish Journal of Geography, vol. 52, Jan. 1953, https://tidsskrift.dk/geografisktidsskrift/article/view/46129.