@article{9572,
  author = {M. McCusker and L. Hatfield and G. Walters},
  title = {Cumulative Ionization in Optically Pumped Helium Discharges: A Source of Polarized Electrons},
  year = {1972},
  journal = {Physical Review A},
  volume = {5},
  pages = {177-189},
  month = {Jan-01-1972},
  issn = {0556-2791},
  url = {http://link.aps.org/doi/10.1103/PhysRevA.5.177},
  doi = {10.1103/PhysRevA.5.177},
}