Gaya APA
dkk, P, R. (2007).
The Blue Marble 2 More About Geography Activity Book [Normal (Academic)] .
Singapore:
Pearson Longman.
Gaya MLA
dkk, Pask, Raymond,.
"The Blue Marble 2 More About Geography Activity Book [Normal (Academic)]".
Singapore:
Pearson Longman,
2007.
Text.