Ryan, William T.
Richard D. Irwin, 1981
Buku Teks
Sheth, Jagdish N., author
John Wiley & Sons, 1988
Buku Teks
Taylor, Weldon Johnson, 1908-, author
South-Western Publishing, 1975
Buku Teks
Thorelli, H.B., author
Penguin Books, 1973
Buku Teks
Dewey, Alice G., author
The Free Press, 1962
Buku Teks