@misc{indiciaefe047e0cb71b,
  title = {A multiloop generalization of the circle criterion for stability margin analysis},
  author = {Safonov, M. G. and Athans, M.},
  year = {1981},
  url = {https://ntrs.nasa.gov/citations/19810048231},
  note = {Source identifier: 19810048231}
}