Gaya APA
Walidi, .
(2006).
Step by step to speaking english
.
Yogyakarta:
Yogyakarta: Citra Adi Parama, 2006.
Gaya MLA
Walidi, .
"Step by step to speaking english".
Yogyakarta:
Yogyakarta: Citra Adi Parama, 2006,
2006.
.