Gaya APA

Sumardy, M, S, D, H. (2011). Customer Loyalty Playbook How Net Promoter Increases Loyalty, Advocacy & Financial Growth (Ed. 1). Jakarta: Upnormals Publishing.

Gaya MLA

Sumardy, Marlin, Silviana, Dan, Harsono. "Customer Loyalty Playbook How Net Promoter Increases Loyalty, Advocacy & Financial Growth". Ed. 1 Jakarta: Upnormals Publishing, 2011. book.