Martin, Gary J.
Chapman and Hall, 1995
Buku Teks
Donnelly, Thomas C.
The University of New mexico Press, 1953
Buku Teks
Dullemen, Inez van
Querido, 1988
Buku Teks
Vaillant, George C.
Penguin Books, 1944
Buku Teks
Pick, James B.
Westview , 1989
Buku Referensi