TY  - BOOK
AU  - Stallings, William
TI  - ISDN An Introduction 
SN  - 0024154717
U1  - 004.6 
PY  - 1989///
CY  - New York : 
PB  - Macmillan, 
KW  - Integrated Services Digital Networks
N1  - YY
UR  - https://eaklibrary.neduet.edu.pk:8443/catalog/bk/books/toc/0-02-415471-7.pdf
ER  -