Baker, Colin
Multilingual Matters Ltd., 1995
Buku Referensi
Ward, Tara
Arcturus Publishing Ltd, 2008
Buku Teks
Rorden, Judith Waring
W.B. Saunders Company, 1987
Buku Teks
Baker, Colin
Multilingual Matters Ltd, 1995
Buku Teks
edited by John P. Holdren, Eric Donald Hirsch
Delta Pub., 1996
Buku Teks