Vidal, Eduardo
Global Law and Business, 2011
Buku Teks SO
Loss, Louis
Little, Brown , 1988
Buku Teks
Hills, George S.
Garland Pubishing, 1982
Buku Teks
Israels, Carlos L.
Warren, Gorham and Lamont,Inc., 1971
Buku Teks
Skoisen, K. Fred
South-Western Piblishing , 1983
Buku Teks SO