Cox, William E. Jr.
N.Y. John Wiley c., 1979
Buku Teks
Howard, John A., author
Richard D. Irwin, 1957
Buku Teks
Keegan, Warren J., author
Prentice Hall of India, 1982
Buku Teks
Rexroad, Robert A.
John Wiley & Sons, 1983
Buku Teks
Gronroos, Cristian
Lexington Book6c1990, 0
Buku Teks