@article{9444,
  author = {D. Heddle},
  title = {An afocal electrostatic lens},
  year = {1971},
  journal = {Journal of Physics E: Scientific Instruments},
  volume = {4},
  pages = {981-983},
  month = {Jan-12-1971},
  issn = {0022-3735},
  url = {http://stacks.iop.org/0022-3735/4/i=12/a=013?key=crossref.e4af44d05a87de8a606775ac1aea9127},
  doi = {10.1088/0022-3735/4/12/013},
}