APA aipamena

Ashok Singh. (2019). UPSC Civil services prelims: General studies-1. wiley.

Chicago Style aipamena

Ashok Singh. UPSC Civil Services Prelims: General Studies-1. New Delhi: wiley, 2019.

MLA aipamena

Ashok Singh. UPSC Civil Services Prelims: General Studies-1. wiley, 2019.