Gaya APA
Riyanto, S., Nien, .
(2012).
Speaking English is easy
.
Yogyakarta:
Pustaka Widyatama.
Gaya MLA
Riyanto, Slamet., Nien, .
"Speaking English is easy".
Yogyakarta:
Pustaka Widyatama,
2012.
Text.