@misc{indiciae36c7dbffdd77,
  title = {Variations on a spherically symmetrical accretion flow},
  author = {Petterson, J. A. and Silk, J. and Ostriker, J. P.},
  year = {1980},
  url = {https://ntrs.nasa.gov/citations/19800049776},
  note = {Source identifier: 19800049776}
}