Kiddey, Rachael, author
Oxford University Press, 2017
Buku Teks
Steve J. Hothersall, Mike Maas-Lowit
Learning Matters Ltd., 2010
Buku Teks
Jay, Rosemary, author
Sweet & Maxwell , 2012
Buku Teks
edited by David Clark
Open University Press , 1993
Buku Teks
Litton, Roger A., 1944-, author
Avebury, 1990
Buku Teks