Taylor, Ian R.
Routledge, 1994
Buku Teks
edited by, Ronald A. Farell and Victoria Lynn Swiger
J.B.Lippincott, 1975
Buku Teks SO
Adler, Patricia A.
Wadsworth, 2000
Buku Teks SO
Suchar, Charles S.
Holt, Rinehart and Winston, 1978
Buku Teks SO
Little, Craig B.
F.E. Peacock Publishers, 1989
Buku Teks