Thickness effects of electret and polymer for energy harvesting: Case of CYTOP- CTLM and polyurethaneFouad Belhora, Daniel Guyomar, M’Hammed Mazroui, Abdelowahed Hajjaji and Yahia BoughalebEur. Phys. J. Plus, 130 2 (2015) 20DOI: https://doi.org/10.1140/epjp/i2015-15020-x