TY  - RPRT
TI  - ISDN conformance testing, layer 1 - physical layer 
AU  - Wakid, Shukri A
AU  - Roberts, Kathleen M
PY  - 1991
PB  - National Institute of Standards and Technology
CY  - Gaithersburg, MD
SN  - NIST SP 500-194
DO  - 10.6028/NIST.SP.500-194
ER  -