APA استشهاد

Chopra, P. S., & Chopra , J. K. (2005). UNIQUE QUINTESSENCE for UPSC Civil services (24.). Unique Publishers.

استشهاد بنمط شيكاغو

Chopra, P. S., و J. K. Chopra. UNIQUE QUINTESSENCE for UPSC Civil Services. 24. New Delhi: Unique Publishers, 2005.

MLA استشهاد

Chopra, P. S., و J. K. Chopra. UNIQUE QUINTESSENCE for UPSC Civil Services. 24. Unique Publishers, 2005.