Munby, John
Cambridge Uniiversity Press , 1985
Buku Teks
Murray, Neil, author
Cambridge University Press, 2015
eBooks
Annisa Nur Hanani, author
2017
UI - Makalah dan Kertas Kerja
Cambridge University Press, 2009
eBooks
Montgomery, Martin, author
Routledge, Taylor & Francis Group, 2008
Buku Teks