edited by Trevor Harley
Sage, 2011
Buku Teks
Garman, Michael
Cambridge University Press, 1990
eBooks
Warren, Paul, 1958-
[Cambridge University Press, ], 2013
eBooks
Steinberg, Danny D.
Longman, 1982
Buku Teks
Berlin : Mouton Publishers
Majalah, Jurnal, Buletin