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2. K. M. Salikhov, A. G. Semenov, and Yu. D. Tsvetkov, The Electron Spin Echo and Its Applications [in Russian] Nauka, Novosibirsk (1976).
3. S. A. Dikanov, V. F. Yudanov, and Yu. D. Tsvetkov, Zh. Strukt. Khim.,18, 460 (1977).
4. L. Kevan, in L. Kevan and R. N. Schwartz (editors), Time Domain Electron Spin Resonance, Wiley-Interscience, New York (1979, Chapter 8.
5. S. A. Dikanov and Yu. D. Tsvetkov, Zh. Strukt. Khim.,20, 824 (1979).