Langer, William L.
Harper Torchbooks, 1969
Buku Teks
Robinson, Marguerite S.
Oxford University Press, 1988
Buku Teks
Kotter, John P., 1947-
The Free Press, 1990
Buku Teks
Rosen, George
University California Press, 1966
Buku Teks
Srinivas, M.N.
University of California Press, 1973
Buku Teks