Gaya APA
HUDA. (2008).
BUSINESS LETTERS .
SURABAYA:
Indah.
Gaya Chicago
HUDA.
BUSINESS LETTERS.
SURABAYA:
Indah,
2008.
Text.
Gaya MLA
HUDA.
BUSINESS LETTERS.
SURABAYA:
Indah,
2008.
Text.
Gaya Turabian
HUDA.
BUSINESS LETTERS.
SURABAYA:
Indah,
2008.
Print.