TY  - BOOK
AU  - Held, 1943- 
TI  - Understanding data communications : from fundamentals to networking 
SN  - 047196820X
U1  - 004.6 HEL 1999 
PY  - 1999///
CY  - Chichester
PB  - John Wiley & Sons
KW  - Computer networks
KW  - Data transmission systems
N1  - Includes index
ER  -