Great Northern Railway Company (U.S.). (1921). Zone of plenty: Minnesota, North Dakota, Montana, Washington, Oregon, Idaho. Great Northern Railway.
Cita Chicago Style (17a ed.)Great Northern Railway Company (U.S.). Zone of Plenty: Minnesota, North Dakota, Montana, Washington, Oregon, Idaho. [Saint Paul, Minn.]: Great Northern Railway, 1921.
Cita MLA (8a ed.)Great Northern Railway Company (U.S.). Zone of Plenty: Minnesota, North Dakota, Montana, Washington, Oregon, Idaho. Great Northern Railway, 1921.
Precaución: Estas citas no son 100% exactas.