Gaya APA
Step Ahead 1 : Activity Book. (2006).
Singapura:
Panpac Education.
Gaya Chicago
Step Ahead 1 : Activity Book.
Kedua.
Singapura:
Panpac Education,
2006.
Printed Book.
Gaya MLA
Step Ahead 1 : Activity Book.
Kedua.
Singapura:
Panpac Education,
2006.
Printed Book.
Gaya Turabian
Step Ahead 1 : Activity Book.
Singapura:
Panpac Education,
2006.
Printed Book.