APA (7 वां संस्करण) प्रशस्ति पत्र

Knapp, D. (2015). A guide to customer service skills for the service desk professional (4th edition.). Cengage Learning.

शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र

Knapp, Donnz. A Guide to Customer Service Skills for the Service Desk Professional. 4th edition. Boston, Massachusetts: Cengage Learning, 2015.

एमएलए (9वां संस्करण) प्रशस्ति पत्र

Knapp, Donnz. A Guide to Customer Service Skills for the Service Desk Professional. 4th edition. Cengage Learning, 2015.