@misc{indiciae4d1017dd5ced,
  title = {Positronium formation in positron-hydrogen scattering.},
  author = {Fels, M. F. and Mittleman, M. H.},
  year = {1967},
  url = {https://ntrs.nasa.gov/citations/19680031009},
  note = {Source identifier: 19680031009}
}