TY  - BOOK
AU  - Roddy, Dennis
AU  - Coolen, John -jt.auth.
TI  - Electronic communications
SN  - 0-87692-396-1
U1  - 621.38 
PY  - 1991///
CY  - N.Delhi
PB  - prentice-Hall
KW  - Electronic communication
ER  -