@misc{indiciae2ca36afcfa6b,
  title = {Chimpanzee sleep stages.},
  author = {Freemon, F. R. and Mcnew, J. J. and Adey, W. R.},
  year = {1971},
  url = {https://ntrs.nasa.gov/citations/19720026408},
  note = {Source identifier: 19720026408}
}