Nichols, Eugene D.
Holt, Rinehart and Winston, 1971
Buku Teks
Nichols, Eugene D.
Rinehart Press, 1975
Buku Teks
Krause, Eugene F.
Prentice-Hall, 1978
Buku Teks
Paige, Donald D.
Prindle, Weber & Schmidt Inc., 1969
Buku Teks
Willson, Jack D.
McGraw-Hill , 1967
Buku Teks