Bellamy, J. (2000). Digital telephony (3rd ed.). Wiley India.
Lua i Stíl Chicago (17ú heag.)Bellamy, John. Digital Telephony. 3rd ed. New York ; New Delhi: Wiley India, 2000.
Lua MLA (8ú heag.)Bellamy, John. Digital Telephony. 3rd ed. Wiley India, 2000.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.