Hughes, Rebecca, author
Pearson Education, 2002
Buku Teks
Nation, I.S.P., author
Heinle Cengage Learning, 2011
Buku Teks
edited by Jonathan Watson and Stephen Platt
Routledge, 2000
Buku Teks
edited by David Kelleher and Sheila Hillier
Routledge, 1996
Buku Teks
edited by Nigel Gilbert
Sage, 2003
Buku Teks