@misc{indiciaef7347482ddc4,
  title = {Negative affinity X-ray photocathodes},
  author = {Vanspeybroeck, L. and Kellogg, E. and Murray, S. and Duckett, S.},
  year = {1974},
  url = {https://ntrs.nasa.gov/citations/19740043161},
  note = {Source identifier: 19740043161}
}