@article{XiaGerhardKuenstleretal.1999,
  author    = {Zhongfu Xia and Reimund Gerhard and Wolfgang K{\"u}nstler and Armin Wedel and Rudi Danz},
  title     = {High surface-charge stability of porous polytetrafluoroethylene electret films at room and elvated temperatures},
  year      = {1999},
}