@article{PhysRevFocus.8.9,
  title = {A Constant that Isn't Constant},
  author = {Berg, Rob van den},
  journal = {Phys. Rev. Focus},
  volume = {8},
  issue = {},
  pages = {9},
  numpages = {1},
  year = {2001},
  month = {Aug},
  doi = {10.1103/PhysRevFocus.8.9},
  url = {http://link.aps.org/doi/10.1103/PhysRevFocus.8.9},
  publisher = {American Physical Society}
}