Gaya APA
Tschohl, J. (2003).
Achieving Excellence through customer service unggul bersaing melalui layanan pelanggan .
:
Gramediaa.
Gaya MLA
Tschohl, John.
"Achieving Excellence through customer service unggul bersaing melalui layanan pelanggan".
:
Gramediaa,
2003.
.