Gaya APA
R.Cooper, D., S.Scheindler, P.
(2014).
Business Research Methods
.
singapur:
Mc Graw-Hill international.
Gaya MLA
R.Cooper, Donald., S.Scheindler, Pamela.
"Business Research Methods".
singapur:
Mc Graw-Hill international,
2014.
BUKU.