@article{5058,
  author = {Sydney Geltman},
  title = {Volkov limit for atomic ionization by ultraintense laser fields},
  year = {1992},
  journal = {Physical Review A},
  volume = {45},
  pages = {5293-5296},
  month = {Jan-04-1992},
  issn = {1050-2947},
  doi = {10.1103/PhysRevA.45.5293},
}