@misc{indiciae23d12bc98ed3,
  title = {The frequency locked loop},
  author = {Clarke, K. K. and Tepedelenlioglu, N. and Unkauf, M.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19680007512},
  note = {Source identifier: 19680007512}
}