Wells, Walter
Kent Publishing Company, 1985
Buku Teks
Murphy, Herta A., author
McGraw-Hill, 1991
Buku Teks
Murphy, Herta A., author
McGraw-Hill, 1976
Buku Teks
Archer, Robert M., author
Prentice-Hall, 1971
Buku Teks
Sherman, Kenneth, author
Reston Publishing company, 1981
Buku Teks