Morgan, Scott, author
Cambridge University Press, 2006
Buku Teks
Irwin, Terry
Churchill Livingstone, 2004
Multimedia
Irwin, Terry., author
Elsevier, 2007
Buku Teks
Lehman, Carol M., author
Thomson South-Western, 2006
Buku Teks
Turock, Betty J., author
Neal-Schuman Publishers, 1992
Buku Teks