1. Alpert, Ya. I., , Radio Wave Propagation and the Ionosphere, , 1 and 2, Consultants Bureau, New York, 1973,
2. Budden, K. G., , Radio Waves in the Ionosphere, Cambridge University Press, New York, 1961,
3. Budden, K. G., , The Propagation of Radio Waves (the theory of radio wave of low power in the ionosphere and magnetosphere), Cambridge University Press, New York, 1985,
4. Hayakawa, M., , Electromagnetic Wave Engineering, in Japanese Corona Publishing Company, Tokyo, 1992,
5. On the mechanism of reflection of ELF-LF waves from the lower ionosphere;Hayakawa;Trans. Inst. Electron. Comm. Eng. Jpn.,1978