@article{11409,
  author = {D. van Blerkom},
  title = {The Effect of Diffuse Ionizing Radiation in Collisionally Excited Nebulae},
  year = {1968},
  journal = {The Astrophysical Journal},
  volume = {152},
  pages = {963},
  month = {Jan-06-1968},
  issn = {0004-637X},
  url = {http://adsabs.harvard.edu/full/1968ApJ...152..963V},
  doi = {10.1086/149609},
}