Muir, Bernice L.
John Wiley & Sons, 1983
Buku Teks
Cambridge University Press, 2014
Buku Teks
Swales, John M.
The University of Michigan Press, 1994
Buku Teks
Nussbaum, Robert L.
Elsevier , 2016
Buku Teks
Sykes, Bryan
Hodder & Stoughton Ltd., 2014
Buku Teks