Gaya APA
Longman essential activator. (1997).
Boston:
Addison Wesley Longman Limited.
Gaya Chicago
Longman essential activator.
Cet.1.
Boston:
Addison Wesley Longman Limited,
1997.
Text.
Gaya MLA
Longman essential activator.
Cet.1.
Boston:
Addison Wesley Longman Limited,
1997.
Text.
Gaya Turabian
Longman essential activator.
Boston:
Addison Wesley Longman Limited,
1997.
Print.