Gaya APA
American education. (2006).
Boston:
Mc Graw-Hill.
Gaya Chicago
American education.
12th.
Boston:
Mc Graw-Hill,
2006.
Buku.
Gaya MLA
American education.
12th.
Boston:
Mc Graw-Hill,
2006.
Buku.
Gaya Turabian
American education.
Boston:
Mc Graw-Hill,
2006.
Buku.