H. Benmansour, F. A. Castro, M. Nagel, J. Heier, R. Hany, and F. Nüesch, “Ionic Space Charge Driven Organic Photovoltaic Devices”, Chimia, vol. 61, no. 12, p. 787, Dec. 2007, doi: 10.2533/chimia.2007.787.