Chaffee, Ellen E.
Lippincott , 1969
Buku Teks SO
McClintic, J. Robert
John Wiley & Sons, 1980
Buku Teks SO
McClintic, J. Robert
John Wiley & Sons, 1980
Buku Teks SO
Albrecht, Robert L.
John Wiley, 1978
Buku Teks SO
Rhoades, Rodney A.
Little, Brown & Co., 1995
Buku Teks SO