M. Jensen., Kr. “The Exploration of Space. Udg. Af The MacMillan Company, 1960. 160 Sider. 18x25 Cm. 5,50 $”. Geografisk Tidsskrift - Danish Journal of Geography 60 (January 1, 1961). Accessed December 7, 2025. https://tidsskrift.dk/geografisktidsskrift/article/view/46635.