Bayon, Damian Carlos
John Wiley & Sons, 1979
Buku Teks
Crawford, William R., author
Frederick A. Praeger, 1961
Buku Teks
edited by Howard J. Wiarda, Harvey F. Kline
Westview Press, 2007
Buku Teks
Martin, Michael Rheta, author
The Bobbs Merrill, 1968
Buku Referensi
Edicions G. Gilli, S.A. de C.V., 1994
Buku Teks