Page, G. Terry, author
MIT Press, 1980
Buku Referensi
Fox, James R., author
Oceana Publication, 1992
Buku Referensi
Presner, Lewis A., author
John Wiley & Sons, 1991
Buku Referensi
Bledsoe, Robert L., author
ABC-Clio, 1987
Buku Referensi
editor in chief Paul Procter
Cambridge University Press, 1995
Buku Referensi