1. O.S. Wolfbeis (Editor), Fiber Optic Chemical Sensors and Biosensors, Vols. I and II, CRC Press, Boca Raton, FL, 1991.
2. M.J.P. Leiner, O.S. Wolfbeis, in: O.S. Wolfbeis (Editor), Fiber Optic Chemical Sensors and Biosensors, Vol. I, CRC Press, Boca Raton, FL, 1991, p. 359.
3. pH optrode for the complete working range
4. Colorimetric sensor based on two optical fiber couplers