[10]. Central America, vol. II, p. 186.
[11]. Ancient America, pp. 155, 156.
[12]. Ancient America, p. 221.
[13]. Pre-Historic America, p. 156.
[14]. Pre-Historic America, p. 165.
[15]. Ancient America, pp. 222, 223.
[16]. Pre-Historic America, p. 81.
[17]. Ancient Monuments of the Mississippi Valley.
[18]. Footprints of Vanished Races.
[19]. Pre-Historic America, pp. 87, 88.