edited by Anthony Gale, Michael W. Eysenck
John Wiley & Sons, 1992
Buku Referensi
Donald Freeman and Jack C. Richardsand
Cambridge Cambridge University Press 1996
Buku Teks
Brown, Douglas
Pearson Longman, 2007
Buku Teks
Cook, Vivian
ARNOLD, 2001
Buku Teks
edited by Douglas McConatha, Christian Penny, Jordan Schugar, and David Bolton
Igi Global, 2014
Buku Teks