Gaya APA
Progressive english course 2. (2003).
Jakarta:
Great media.
Gaya Chicago
Progressive english course 2.
.
Jakarta:
Great media,
2003.
Text.
Gaya MLA
Progressive english course 2.
.
Jakarta:
Great media,
2003.
Text.
Gaya Turabian
Progressive english course 2.
Jakarta:
Great media,
2003.
Print.