Nielsen N. 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. gt [Internet]. 1. januar 1939 [henvist 24. april 2024];42. Tilgængelig hos: https://tidsskrift.dk/geografisktidsskrift/article/view/48259