Watson, Tony J.
Prentice-Hall, 2002
Buku Teks
Edited by Jennifer G. Hill, Randall S. Thomas
Edward Elgar Publishing, 2015
Buku Teks
Rogers, John
Cloustan and Hall, 1988
Buku Teks
Harper & Row , 1981
Buku Teks
Walters, C. Glenn
South Western Publishing, 1989
Buku Teks