@conference{9958,
  author = {Katharine Gebbie and R. Steinitz},
  title = {Comparison of H alpha and Ca II H and K spectroheliograms as a diagnostic probe},
  year = {1974},
  publisher = {Reidel, Dordrecht, Netherlands},
  address = {Queensland, Australia},
  note = {JILA Pub. 1250},
}