Template-based fluoroethylenepropylene piezoelectrets with tubular channels for transducer applications - Altafim, Ruy Alberto Pisani; Xunlin, Qiu; Wirges, Werner; Gerhard, Reimund; Altafim, Ruy Alberto Corrêa; Basso, Heitor Cury; Jenninger, Werner; Wagner, Joachim (Journal of Applied Physics, 2009)