Hendrix, Jerry A, author
Wadsworth and Cengage Learning, 2007
Buku Teks
Jefkins, Frank William, author
Heinemann Asia, 1992
Buku Teks
Mogel, Leonard
Collier Books Macmillan Publishing, 1993
Buku Teks
Oxley, Harold
Gunung Mulia, 1993
Buku Teks
Cutlip, Scott M., author
Prentice Hall International, 2000
Buku Teks