O`Sullivan, Terence, author
Macmillan, 1999
Buku Teks
Parris, Melanie, author
McGraw-Hill, 2012
Buku Teks
Musson, Philip, author
Learning Matters, 2011
Buku Teks
Heraud, Brian J., author
Routledge & Kegan Paul , 1981
Buku Teks
edited by Margaret Yelloly and Mary Henkel
Jessica Kingsley Publishers, 1995
Buku Teks