Biswal, D., & Rao,J.K. (1980). Commercial correspondence (3rd rev. ed.). Kalyani.
Chicago Style aipamenaBiswal, D., and Rao,J.K. Commercial Correspondence. 3rd rev. ed. Ludhiana: Kalyani, 1980.
MLA aipamenaBiswal, D., and Rao,J.K. Commercial Correspondence. 3rd rev. ed. Kalyani, 1980.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.