@article{SoffMuellerRafelski2014,
  author    = {Gerhard Soff and Berndt M{\"u}ller and Johann Rafelski},
  title     = {Precise values for critical fields in quantum electrodynamics},
  journal   = {Zeitschrift f{\"u}r Naturforschung, A},
  volume    = {29},
  number    = {9},
  pages     = {1267 -- 1275},
  doi       = {10.1515/zna-1974-0905},
  year      = {2014},
}