Biswas, N. N. (1993). Principles of telegraphy.
Cita Chicago (17th ed.)Biswas, Nripendra N. Principles of Telegraphy. New Delhi : Media promoters & Publishers, 1993.
Cita MLA (9th ed.)Biswas, Nripendra N. Principles of Telegraphy. 1993.
Atenció: Aquestes cites poden no estar 100% correctes.