Gaya APA
LUBIS, Y. (1988).
Developing Communicative Proficiency in the English as a foreign Language (EFL) Class .
Jakarta:
DEPDIKBUD.
Gaya MLA
LUBIS, Yusnaini.
"Developing Communicative Proficiency in the English as a foreign Language (EFL) Class".
Jakarta:
DEPDIKBUD,
1988.
Buku.