edited by John O. Haley
Kendall / Hunt, 1988
Buku Teks
Barnes, Harry Elmer
Prentice-Hall, 1950
Buku Teks
Yarmolinsky, Adam.
Twentieth Century Fund., 1971
Buku Teks
Westview Press, 1978
Buku Teks
edited by Howard Nemerov
Voice of America Forum Lectures, 1973
Buku Teks