Walters, Joel
Lawrence Erlbaum Associates, 2005
Buku Teks
edited by Tej K. Bhatia and William C. Ritchie
Wiley Blackwell, 2014
Buku Teks SO
Noor Azam Haji-Othman
ISEAS/BUFS, 2016
Artikel Jurnal
Appel, René
Amsterdam Academic Archive, 2005
Buku Teks
Paradis, Michel
John Benjamins , 2004
Buku Teks SO