Gaya APA
Smile, H. (2011).
Incredible and impression service: 156 kebiasaan efektif orang sales dan customer service .
Sleman:
Shira Media.
Gaya MLA
Smile, Heri.
"Incredible and impression service: 156 kebiasaan efektif orang sales dan customer service".
Sleman:
Shira Media,
2011.
Text.