@misc{indiciae07e47e580443,
  title = {Multi-channel magnetograph observations. I - Comparison with spectroheliograms},
  author = {Frazier, E. N. and Scherrer, P. H.},
  year = {1969},
  url = {https://ntrs.nasa.gov/citations/19700041877},
  note = {Source identifier: 19700041877}
}