Talbot
Buku Teks
Berger, Morroe, author
Anchor Books, 1964
Buku Teks
Stair, Ralph M., Jr., author
Irwin, 1986
Buku Teks
edited by Don Hellriegel and John W. Slocum
Addison- Wesley , 1975
Buku Teks
Israel, Saul, author
Holt, Rinehart and Winston, 1976
Buku Teks