Paige, Donald D.
Prindle, Weber & Schmidt, 1969
Buku Teks SO
Ewen, Dale
Thomson Brooks/Cole, 2007
Buku Teks SO
Krause, Eugene F.
Prentice-Hall, 1978
Buku Teks SO
Nichols, Eugene D.
Holt, Rinehart and Winston, 1971
Buku Teks SO
Peterson, John M.
Prindle, Weber & Schmidt, 1971
Buku Teks SO