Stephen, Revare.
Nexus, 2010
Buku Teks
[publisher not identified], [date of publication not identified]
Buku Teks
Seoul National University Language
Moonji Media, 2007
Buku Teks
Jones, Leo, author
Cambridge University Press, 2011
Buku Teks
Jones, Leo
Cambridge University Press, 2008
Buku Teks