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. Geografisk Tidsskrift, [S. l.], v. 42, 1939. Disponível em: https://tidsskrift.dk/geografisktidsskrift/article/view/48259. Acesso em: 5 maj. 2024.