Gaya APA
Kellas, P., L., L. (2006).
ENGLISH AS A SECOND LANGUAGE: TEACHER'S BOOK .
United Kingdom UK:
Cambridge University Press.
Gaya MLA
Kellas, Peter, Lucantoni,, Lydia.
"ENGLISH AS A SECOND LANGUAGE: TEACHER'S BOOK".
United Kingdom UK:
Cambridge University Press,
2006.
Buku Inti.