Bolton, Herbert E. 1947. The West coast corridor, Proceedings of the American Philosophical Society, Vol. 91, pp. 426-429

Bolton, Herbert E. 1947. The West coast corridor, Proceedings of the American Philosophical Society, Vol. 91, pp. 426-429, Box: 8, Folder: 32. Campbell W. Pennington Papers, 33036864. Benson Latin American Collection, The University of Texas at Austin. https://archives.lib.utexas.edu/repositories/4/archival_objects/279307 Accessed September 26, 2026.