@misc{indiciae41241607ce65,
  title = {A simple analytic approximation for dusty Stroemgren spheres},
  author = {Petrosian, V. and Silk, J. and Field, G. B.},
  year = {1972},
  url = {https://ntrs.nasa.gov/citations/19720026125},
  note = {Source identifier: 19720026125}
}