Rhonda Phillips, Robert H. Pittman, editor
Routledge, 2009
Buku Teks
Boyd, Denise, author
Pearson/Allyn and Bacon, 2009
Buku Teks
Craig, Grace J., author
Prentice-Hall, 1986
Buku Teks
Herrick, Bruce H., author
McGraw-Hill, 1983
Buku Teks
Galbraith, John Kenneth, 1908-2006, author
Harvard U.P, 1964
Buku Teks