Wright, Harry K.
The University of North Caroline Press, 1971
Buku Teks SO
Grayson, George W.
Thomson, 2004
Buku Teks SO
Pick, James B.
Westview , 1989
Buku Referensi
Castillo, Bernal Diaz del
H. Wolf, 1956
Buku Teks
edited by James W. Wilkie, Michael C. Meyer and Edna Monzon de Wilkie
University of California Press, 1976
Buku Teks SO