Fristrup., B. “Colin Bertram: Arctic and Antarctic. A Prospect of the Polar Regions. 16 X 24 Cm. 123 S. W. Heffer Dfc Sons LTD., Cambridge”. Geografisk Tidsskrift - Danish Journal of Geography, vol. 57, Jan. 1958, https://tidsskrift.dk/geografisktidsskrift/article/view/46367.