Cruse, Alan
Oxford University Press, 2013
Buku Teks
Griffths, Patrick
Edinburgh University Press, 2006
Buku Teks
Williams, Alexander
Cambridge University Press, 2015
eBooks
Ullmann, Stephen
Basil Blackwell, 1964
Buku Teks
Valin, Robert D. van
Cambridge University Press, 2005
Buku Teks