@article{9825,
  author = {V. Ehlers and Alan Gallagher},
  title = {Electron Excitation of the Calcium 4227-\r A Resonance Line},
  year = {1973},
  journal = {Physical Review A},
  volume = {7},
  pages = {1573-1585},
  month = {Jan-05-1973},
  issn = {0556-2791},
  doi = {10.1103/PhysRevA.7.1573},
}