1. For a review on electrochromic materials and their properties see papers by J.Bruinink, I.F.Chang, H.R.Zeller: InNon Emissive Electrooptic Displays Brown Boveri Symposium Series, ed. by A. R.Kmetz and F.K.v.Willisen (Plenum Press, London 1976)
2. S.K.Deb: Phil. Mag.27, 801 (1973)
3. J.H.Schulman, W.D.Compton:Color Centers in Solids (Pergamon Press, London 1962)
4. I.F.Chang, W.E.Howard: IEEE Conf. on Display Devices and Systems (1974) p. 148
5. I.F.Chang, B.L.Gilbert, T.I.Sun: J. Electrochem. Soc.122, 955 (1975)