Cook, Chris, author
Routledge, 2005
Buku Teks
Cook, Chris, author
Longman, 1991
Buku Referensi
Routledge, 2021
eBooks
Palmer, Robert Roswell, 1909-2002, author
McGraw-Hill, 1992
Buku Teks
edited by Catherine Spooner, Emma McEvoy
Routledge, 2007
Buku Teks