[14]O. F. Cook, “Staircase Farms of the Ancients,” National Geographic Magazine, 29:513 (1916).
[15]P. C. Mangelsdorf and R. G. Reeves, The Origin of Indian Corn and Its Relatives (Bulletin No. 574, Texas Agricultural Experiment Station, 1939), 7.
[16]Ibid., 7.
[17]Ibid., 8, 7.
[18]Sauer, op. cit., 292.
[19]G. N. Collins, “The Phylogeny of Maize,” Bulletin, Torrey Botanical Club, 57:203 (1930).
[20]Bruman, op. cit., 457.
[21]Sylvanus G. Morley, The Ancient Maya (1946), 386.
[22]MacNeish, op. cit., 27.
[23]Paul C. Mangelsdorf, “Ancestor of Corn,” Science, 128:1314 (1958).