@article{Heilmann2014,
  author    = {Gerhard Heilmann},
  title     = {Die optischen Konstanten von Calciumfluorid im Ultraroten},
  journal   = {Zeitschrift f{\"u}r Naturforschung, A},
  volume    = {16},
  number    = {7},
  pages     = {714 -- 716},
  doi       = {10.1515/zna-1961-0709},
  year      = {2014},
}