Talley, David.
Basic Carrier Telephony / Talley David. - Revised 3 edition. - Rochelle Park, N.J. : Hayden, 1977. - 218 s.; 25 cm.
Basic Carrier Telephony / Talley David. - Revised 3 edition. - Rochelle Park, N.J. : Hayden, 1977. - 218 s.; 25 cm.