TY  - BOOK
AU  - Held, Gilbert
TI  - Understanding data communications
SN  - 0-672-30934-3
U1  - B.C. 004.6 --Fifth edition:
PY  - 1996///
CY  - --U.S.A.
PB  - Sams Publishing
N1  - Includes glossary  bibliography and  index
ER  -