@article{QiuGrothWirgesetal.2018,
  author    = {Xunlin Qiu and Frederick Groth and Werner Wirges and Reimund Gerhard},
  title     = {Cellular polypropylene foam films as DC voltage insulation and as piezoelectrets},
  journal   = {IEEE transactions on dielectrics and electrical insulation},
  series    = {a comparison},
  volume    = {25},
  number    = {3},
  pages     = {829 -- 834},
  doi       = {10.1109/TDEI.2018.007192},
  year      = {2018},
}