Ewen, David, author
Prentice-Hall, 1989
Buku Referensi
Ewen, David, author
Prentice-Hall, 1952
Buku Teks
Hewitt, Terry
Dorling Kindersley, 1993
Buku Teks
Becker, Norman, author
McGraw-Hill , 1980
Buku Teks
Chappell, James
Watson-Guptill Publications, 1991
Buku Teks