@article{11635,
  author = {R. Damburg},
  title = {Threshold law for electron impact excitation of ns-n\textquoterights transitions in atoms},
  year = {1969},
  journal = {Journal of Physics B: Atomic and Molecular Physics},
  volume = {2},
  url = {http://iopscience.iop.org/0022-3700/2/1/121/pdf/0022-3700_2_1_121.pdf},
  note = {JILA Pub. 459},
}