Waitley, Denis
Tianxia Wenhua Chuban, 1983
Buku Teks
Walker, Hilary
Learning Matters Ltd., 2008
Buku Teks
Stevens, R. Paaul
Literature Perkantas IKAPI, 2012
Buku Teks SO
Carol Smallwood, Vera Gubnitskaia, Kerol Harrod, editors
McFarland & Company, 2012
Buku Teks SO
Lehrer, Robert N.
Prentice-Hall, 1982
Buku Teks SO