1. R. Reisfeld, Optical and electronic phenomena in sol–gel glasses and modern applications, in: R. Reisfeld, C.K. Jørgensen (Eds.), Structure and Bonding, vol. 85, Springer, Berlin, 1996, p. 215 (and references therein)
2. The state of art of solid state tunable lasers in the visible
3. O. Wolfbeis, R. Reisfeld, I. Oehme, Sol–gel sensors. Optical and electronic phenomena in sol–gel glasses and modern applications, in: R. Reisfeld, C.K. Jorgensen (Eds.), Structure and Bonding, vol. 85, 1996, p. 51