Roll, Charles W.
Seven Locks Press, 1980
Buku Teks
Yeric, Jerry L.
F.E. Peacock Publishers, 1983
Buku Teks
Hofstadter, Richard
N.Y. Random House , 1967
Buku Teks
McClosky, Herbert, author
Gadjah Mada University Press, 1988
Buku Teks
Burlingame, Roger
Alfred A. Knopf, 1960
Buku Teks