Gaya APA
Encyclopedia Americana Volume 21 (O-P). (2002).
USA:
Grolier Educational.
Gaya Chicago
Encyclopedia Americana Volume 21 (O-P).
vol.21, 2002.
USA:
Grolier Educational,
2002.
Text.
Gaya MLA
Encyclopedia Americana Volume 21 (O-P).
vol.21, 2002.
USA:
Grolier Educational,
2002.
Text.
Gaya Turabian
Encyclopedia Americana Volume 21 (O-P).
USA:
Grolier Educational,
2002.
Print.