@misc{1196511,
  author = {Shukri A Wakid and Kathleen M Roberts},
  title = {ISDN conformance testing, layer 1 - physical layer:},
  year = {1991},
  month = {1991-01-01 05:01:00},
  publisher = {, National Institute of Standards and Technology, Gaithersburg, MD},
  doi = {https://doi.org/10.6028/NIST.SP.500-194},
  language = {en},
}