May, W. Graham
Balisdell , 1967
Buku Teks
Eves, Howard, author
Holt Rinehart and Wilson, 1964
Buku Teks
Craig, Robert T., author
Prentice-Hall, 1969
Buku Teks
Smith, Karl J., author
Brooks/Cole, 1973
Buku Teks
Hafstrom, John E., author
Addison-Wesely, 1961
Buku Teks