Gaya APA
World Book Series. (2006).
Chicago:
World Book.
Gaya Chicago
World Book Series.
-.
Chicago:
World Book,
2006.
Text.
Gaya MLA
World Book Series.
-.
Chicago:
World Book,
2006.
Text.
Gaya Turabian
World Book Series.
Chicago:
World Book,
2006.
Print.