Nielsen, N. (1939) “Atlas of America Agriculture. Physical Basis includingland relief, climate, soils and natural vegetation. U. S. Department of Agriculture. Washington 1936, 231 S., 47X30 cm. Pris: $ 17.”, Geografisk Tidsskrift, 42. Tilgængelig hos: https://tidsskrift.dk/geografisktidsskrift/article/view/48259 (Set: 27februar2021).