@misc{indiciaec664e53a6832,
  title = {Infrared-line emission from planetary nebulae.},
  author = {Delmer, T. N. and Gould, R. J. and Ramsay, W.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19670063082},
  note = {Source identifier: 19670063082}
}