Beatley, Timothy, author
University California Press, 2003
Buku Teks
Hiam, Alexander, author
Prentice-Hall, 1992
Buku Teks
edited by Gary Hoover, Alta Campbell, Patrick Spain
The Reference Press, 1991
Buku Referensi
Drucker, Peter F. (Peter Ferdinand), 1909-2005, author
Pan Books, 1982
Buku Teks
Drucker, Peter F. (Peter Ferdinand), 1909-2005, author
Harper & Row, 1945
Buku Teks