Gaya APA
Roger, U, D. (2010).
Research methods for business: a skill building approach fifth edition. s2 .
india:
jhon wiley.
Gaya MLA
Roger, Umasekaran, Dan.
"Research methods for business: a skill building approach fifth edition. s2".
india:
jhon wiley,
2010.
Buku PPS Manajemen.