Gaya APA
Riyanto, S.
(2010).
LET'S SPEAK ENGLISH ACTIVELY
.
Yogyakarta:
PUSTAKA PELAJAR.
Gaya MLA
Riyanto, Slamet.
"LET'S SPEAK ENGLISH ACTIVELY".
Yogyakarta:
PUSTAKA PELAJAR,
2010.
Text.