TY  - BOOK
AU  - Black,Uyless
TI  - Data networks : : consepts, theory, and practice 
SN  - 9718636358
U1  - 621.3811  
PY  - 1989///
CY  - Englewood Cliffs (N.J.) : 
PB  - Prentice Hall, 
KW  - 	 Computer networks
KW  - Data transmission systems
ER  -