Gaya APA
Manurung, Heldin. (2003).
Progressive English Course 1 .
Jakarta:
Great Media.
Gaya Chicago
Manurung, Heldin.
Progressive English Course 1.
Jakarta:
Great Media,
2003.
Text.
Gaya MLA
Manurung, Heldin.
Progressive English Course 1.
Jakarta:
Great Media,
2003.
Text.
Gaya Turabian
Manurung, Heldin.
Progressive English Course 1.
Jakarta:
Great Media,
2003.
Print.