@article{FangWegenerWirgesetal.2007,
  author    = {Peng Fang and Michael Wegener and Werner Wirges and Reimund Gerhard and Larissa Zirkel},
  title     = {Cellular polyethylene-naphthalate ferroelectrets : foaming in supercritical carbon dioxide, structural and electrical preparation, and resulting piezoelectricity},
  doi       = {10.1063/1.2738365},
  url       = {http://apl.aip.org/},
  year      = {2007},
}