Baba, A., Lübben, J., Tamada, K., & Knoll, W. (2003). Optical properties of ultrathin poly(3,4-ethylenedioxythiophene) films at several doping levels studied by in situ electrochemical surface plasmon resonance spectroscopy. Langmuir, 19(21), 9058-9064. doi:10.1021/la034848n.