@misc{indiciaefdb61f31844d,
  title = {Man-made space debris - Does it restrict free access to space},
  author = {Wolfe, M. and Chobotov, V. and Kessler, D. and Reynolds, R.},
  year = {1981},
  url = {https://ntrs.nasa.gov/citations/19810063024},
  note = {Source identifier: 19810063024}
}