3) K. Chan, H. Ito, and H. Inaba; “10km-Long Fibre - Optic Remote Sensing of C Gas by Near Infrared Absorption”, Appl. Phys. B38, pp. 11-15 (1985)
4) Jonas Sandsten, Hans Edner, and Sune Svanberg ; “Gas imaging by infrared gas-correlation spectrometry”, OPTICS LETTERS, Vol. 21, No. 23, pp. 1945-1947 (1996)
5) T. J. Kulp, Peter Powers, Randall Kennedy, and Uta-Barbara Goers;“Development of a pulsed Backscatter-adsorption gas-imaging system and its application to the visualization of natural gas leaks”, Appl. Opt. , Vol. 37, No. 18, pp. 3912-3922 (1998)