Bhatnagar, P. (2008). Written communication. Rajat Publications.
Chicago Style aipamenaBhatnagar, Piyush. Written Communication. New Delhi: Rajat Publications, 2008.
MLA aipamenaBhatnagar, Piyush. Written Communication. Rajat Publications, 2008.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.