TY  - BOOK
AU  - Held, Gilbert
TI  - Undestanding data communications : : from fundamentals to networking 
SN  - 0471968200
AV  - TK 5105 H44 1998 CIRC 
PY  - 1998///
CY  - Chichester
PB  - John Wiley & Sons, 
KW  - Data transmission systems
KW  - Computer networks
N1  - Includes index
ER  -