Bellamy, J. (2003). Digital telephony (3rd ed.). Wiley.
Lua i Stíl Chicago (17ú heag.)Bellamy, John. Digital Telephony. 3rd ed. New York ; Singapore: Wiley, 2003.
Lua MLA (8ú heag.)Bellamy, John. Digital Telephony. 3rd ed. Wiley, 2003.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.