@misc{indiciaece5fa9322297,
  title = {Telephone multiline signaling using common signal pair},
  author = {Goodloe, R. R. and Toole, P. C. and Belt, J. L. and Leininger, D. B.},
  year = {1979},
  url = {https://ntrs.nasa.gov/citations/19790015139},
  note = {Source identifier: 19790015139}
}