Sheth, Jagdish N.
Free Press, 2002
Buku Teks
Mohammad Sadli, 1922-2008
Fakultas Ekonomi Universitas Indonesia, [date of publication no identified]
Buku Teks
Shepherd, William G.
Prentice-Hall, 1979
Buku Teks
Lesourne, Jacques
Englewood Cliffs, N.J., Prentice-Hall
Buku Teks
1982, George Allen & Unwin
Buku Teks