1. Solid-State Gas Sensors;Moseley,1987
2. H.D. Le Vine, Method and apparatus for operating a gas sensor, US Patent 3906473 (16 September 1975).
3. H. Eicker, Method and apparatus for determining the concentration of one gaseous component in a mixture of gases, US Patent 4012692 (15 March 1977).
4. L.J. Owen, Gas monitors, US Patent 4185491 (29 January 1980).
5. G.N. Advani, R. Beard, L. Nanis, Gas measurement method, US Patent 4399684 (23 August 1983).