Gaya APA
Kon, T., Nustad, H. (1991).
Practical English Usage: English As A Second Language 4 .
Jakarta:
Binarupa Aksara.
Gaya MLA
Kon, TS., Nustad, Harry.
"Practical English Usage: English As A Second Language 4".
Jakarta:
Binarupa Aksara,
1991.
Text.