1. M. M. Lavrent'yev, V. G. Romanov, and S. P. Shishatskii, Incorrect Problems of Mathematical Physics and Analysis [in Russian], Moscow (1980).
2. A. N. Tikhonov and A. A. Samarskii, Equations of Mathematical Physics [in Russian], Moscow (1972).
3. A. D. Kovalenko, Fundamentals of Thermoelasticity [in Russian], Kiev (1970).
4. I. B. Basovich, Prikl. Mat. Mekh.,38, No. 3, 376?383 (1974).
5. A. D. Iskenderov, Izv. Akad. Nauk AzSSR, No. 2, 14?21 (1971).