1. Bellcore 1987, “Characterization of Subscriber Loops for Voice and ISDN Services: 1983 Subscriber Loop Survey Results,” Science and Technology Series, ST-TSY-000041
2. Bellcore 1986}, “NYNEX Loop Performance Survey: Report of Results,” Loop Survey Report
3. R.P.S. Singh 1987, “The LAST Bell System Subscriber Loop Survey,” Telephony, October 5
4. S.V. Ahamed and R.A. McDonald 1985, “Calculation of Insertion Losses in Loops in the 1983 Loop Survey Data Base at Frequencies Relevant for ISDN Basic Access,” T1D1.3 Contribution, Vancouver, British Columbia, August 19–23
5. S.V. Ahamed and R.P.S. Singh, 1986, “Physical and Transmission Characteristics of Subscriber Loops for ISDN Services,” Record of the ICC’86, June 22-25, 1211–1215