@article{9617,
  author = {W. Peterson and Earl Beaty and C. Opal},
  title = {Measurements of Energy and Angular Distributions of Secondary Electrons Produced in Electron-Impact Ionization of Helium},
  year = {1972},
  journal = {Physical Review A},
  volume = {5},
  pages = {712-723},
  month = {Jan-02-1972},
  issn = {0556-2791},
  doi = {10.1103/PhysRevA.5.712},
}