@misc{indiciae00bc66c3616c,
  title = {Studies in spectral line formation. III - Non-linear multi-level atom problems.},
  author = {Finn, G. D. and Jefferies, J. T.},
  year = {1969},
  url = {https://ntrs.nasa.gov/citations/19690048978},
  note = {Source identifier: 19690048978}
}