Freeland, Cynthia A., author
Oxford University Press, 2001
Buku Teks
Robinson, Geoffrey A.
Butterworth, 1966
Buku Teks
Barnett, H.G., author
Row, Peterson , 1956
Buku Teks
Kilgannon, Pete, author
McGraw-Hill, 1980
Buku Teks
Urwick, Lyndall F., author
Harper & Brothers, 1960
Buku Teks