@misc{indiciaef123abd1cf9c,
  title = {Electron and bremsstrahlung penetration and dose calculation},
  author = {Watts, J. W., Jr. and Burrell, M. O.},
  year = {1972},
  url = {https://ntrs.nasa.gov/citations/19720010059},
  note = {Source identifier: 19720010059}
}