Ewen, Dale
Thomson Brooks/Cole, 2007
Buku Teks
Connelly, James F.
Macmillan, 1978
Buku Teks
Schaaf, William L.
Wiley-Academy, 1965
Buku Teks
Devine, Donald F.
John Wiley & Sons, 1977
Buku Teks
Washington, Allyn J.
Pearson - Prentice Hall, 2009
Buku Teks