Digital telephony
Bellamy, John C.
Digital telephony - 3rd edition. - New York : John Wiely Publisher, 1994 - 643.
9814126357
Applied physics
621.385 / BEL
Digital telephony - 3rd edition. - New York : John Wiely Publisher, 1994 - 643.
9814126357
Applied physics
621.385 / BEL