Kennedy, Eugene
Free Press , 1997
Buku Teks SO
David, Kingley
Rinehart, 1951
Buku Teks
edited, John B. Williamson, Linda Evans and Michael Rustad
Little, Brown, 1985
Buku Teks SO
Currie, Elliott
Little, Brown, 1984
Buku Teks SO
Howard, John R.
J.B. Lippincott, 1974
Buku Teks SO