Berger, Morroe, author
Anchor Books, 1964
Buku Teks
Srewart, Desmond
New York : Time Incorporated, c.1962.
Buku Teks
Talbot
Buku Teks
Stair, Ralph M., Jr., author
Irwin, 1986
Buku Teks
edited by Don Hellriegel and John W. Slocum
Addison- Wesley , 1975
Buku Teks