Ladd, Everett Carll.
W.W. Norton , 1972
Buku Teks SO
Vogel, Ezra F.
Univertity of California Press, 1967
Buku Teks
edited with introductions by Michael Bromley, Tom O'Malley
Routledge , 1997
Buku Teks
Fjeldstad, Mary C.
Harcourt Brace College Publisher, 1998
Buku Teks
David J. Whittaker
Routledge, 2001
Buku Teks