Não informado. (1938). Current Geographical Publications. American Geographical Society Collection.
Chicago-referens (17:e uppl.)Não informado. Current Geographical Publications. Milwaukee, Wis: American Geographical Society Collection, 1938.
MLA-referens (8:e uppl.)Não informado. Current Geographical Publications. American Geographical Society Collection, 1938.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.