Ogburn, C., & Sugar, J. A. (1977). Railroads, the great American adventure. The National Geographic Society.
Cita Chicago Style (17a ed.)Ogburn, Charlton, y James A. Sugar. Railroads, the Great American Adventure. Washington: The National Geographic Society, 1977.
Cita MLA (9a ed.)Ogburn, Charlton, y James A. Sugar. Railroads, the Great American Adventure. The National Geographic Society, 1977.
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