Harvester Wheatsheaf , 1992
Buku Teks
Howard, Darlene V., author
Macmillan, 1983
Buku Teks
Mayer, Richard E., author
W.H. Freeman, 1983
Buku Teks
Bono, Edward de, author
Penguin Books, 1971
Buku Teks
Berlyne, D.E.
John Wiley & Sons Inc., 1966
Buku Teks