Schwab, William A.
Prentice-Hall, 1992
Buku Teks
Karp, David A., author
Praeger, 2015
Buku Teks
Sage pub., 2014
Buku Teks
Cousins, Albert N., 1919-, author
John Wiley & Sons, 1979
Buku Teks
Stevenson, Deborah, author
Open University Press, 2003
Buku Teks