Humphrey, Don D., author
Frederick A. Praeger , 1962
Buku Teks
Dean, Vera Micheles
Alfred.A.Knopf, 1950
Buku Teks
Randall, Clarence B.
The University of Chicago Press, 1954
Buku Teks
Benoit, Emile
Columbia University Press, 1962
Buku Teks
McGovern, Edmond, author
Globefield Press, 1982
Buku Teks