Dörnyei, Zoltán, author
Cambridge University Press, 2004
Buku Teks
Schmuck, Richardo, author
WM. C. Brown company publisher , 1983
Buku Teks
Allwright, Dick, author
Longman, 1993
Buku Teks
Lemke, J.L. (Jay L.), author
Oxford University Press, 1989
Buku Teks
Stevick, Earl W.
Cambridge Cambridge University Press 1991,
Buku Teks