APA (7 वां संस्करण) प्रशस्ति पत्र

Khullar, D. (2018). Indian and world geography for civil services preliminary examination. CL Media.

शिकागो शैली (17वां संस्करण) प्रशस्ति पत्र

Khullar, D.R. Indian and World Geography for Civil Services Preliminary Examination. Roorkee: CL Media, 2018.

एमएलए (9वां संस्करण) प्रशस्ति पत्र

Khullar, D.R. Indian and World Geography for Civil Services Preliminary Examination. CL Media, 2018.