Biswas, N. N. (1993). Principles of telegraphy.
Chicago Style (17th ed.) ZitazioaBiswas, Nripendra N. Principles of Telegraphy. New Delhi : Media promoters & Publishers, 1993.
MLA (9th ed.) ZitazioaBiswas, Nripendra N. Principles of Telegraphy. 1993.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.