Gaya APA
Christensen, L, B. et al
(2015).
Research Methods, Design, and Analysis : TWELFTH EDITION
.
Inggris:
Pearson.
Gaya MLA
Christensen, Larry, B. et al.
"Research Methods, Design, and Analysis : TWELFTH EDITION".
Inggris:
Pearson,
2015.
Text.