Williamson, J. Peter (John Peter), author
Scott, Foresman, 1968
Buku Teks
Gaffney, Dennis J., author
McGraw-Hill, 1982
Buku Teks
Gaffney, Dennis J., author
McGraw-Hill, 1984
Buku Teks
Prentice-Hall, 1976
Buku Teks
Hudson, David M., author
St. Paul, Minn, 1994
Buku Teks