Griffith, Martin
Routledge, 2002
Buku Teks
edited by Beth A. Simmons and Richard H. Steinberg
Cambridge University Press, 2006
Buku Teks
Deutsch, Karl Wolfgang, 1912-1992
Prentice-Hall, 1988
Buku Teks
edited by William T.R. Fox
Indiana University of Notre Dame Press , 1959
Buku Teks
Reynolds, P.A.
Longman, 1994
Buku Teks