R. Masri Sareb Putra, author
Kolbu, 2007
Buku Teks
Jordan, R. R.
Collins ELT, 1980
Buku Teks
Ricketson, Matthew, author
Allen & Unwin, 2017
Buku Teks
Sharples, Mike, 1952-, author
Routledge, 1999
Buku Teks
Johnson, Falk S., author
Houghton Mifflin, 1965
Buku Teks