Bellamy, J. (1982). Digital telephony. Wiley-Interscience.
Lua i Stíl Chicago (17ú heag.)Bellamy, John. Digital Telephony. New York: Wiley-Interscience, 1982.
Lua MLA (9ú heag.)Bellamy, John. Digital Telephony. Wiley-Interscience, 1982.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.