1. V. P. Grozov, “Processing of Ionograms — Statistical Approach,” in Proc. Int. Symp. on Radio Propagation (ISRP’97) (Qingdao, 1997), pp. 225–228.
2. B. W. Reinisch and H. Xuegin, “Automatic Calculation of Electron Density Profiles from Digital Ionograms,” Radio Sci. 18(3), 477–492 (1983).
3. W. K. Pratt, Digital Image Processing (New York, 1978), Vols. 1, 2.
4. L. P. Yaroslavskii, Introduction into Digital Data Processing (Sov. Radio, Moscow, 1979) [in Russian].
5. V. P. Grozov, V. E. Nosov, G. A. Ososkov, and E. G. Zaznobina, “Artificial Neural Networks for Computer-Aided Ionogram Analysis,” in Computer Aided Processing of Ionograms and Ionosonde Records, Ed. by P. J. Wilkinson (Boulder, 1998), pp. 30–34.