@misc{indiciaea5dfd18360a1,
  title = {Atomic hydrogen in planetary nebulae},
  author = {Schneider, Stephen E. and Silverglate, Peter R. and Altschuler, Daniel R. and Giovanardi, Carlo},
  year = {1987},
  url = {https://ntrs.nasa.gov/citations/19870049388},
  note = {Source identifier: 19870049388}
}