1. R.Beck, et al.,Table of Laser Lines in Gases and Vapors, 3rd edition, Springer-Verlag (1980)
2. C.O.Weiss, et al., in Reviews of Infrared and Millimeter Waves, Vol.2, ed by K.J.Button, (1984).
3. Y.Lin, et al., The 17th Int. Conf. on IR and MMW. Digest 312, (1992).
4. Y.Li,et al., Int.J.IR-MMW. V.14, 3, (1993).
5. R.Ulrich, et al., IEEE Trans. MTT-11, 5, 363, (1963)