Gaya APA
Gal, M, D. et al
(2003).
Education Research An Introduction
(
Ed. 7)
.
America:
Pearson Education.
Gaya MLA
Gal, Meredith, D.. et al.
"Education Research An Introduction".
Ed. 7
America:
Pearson Education,
2003.
Buku PPS Pend. Biologi.