1. S. Agmon, Lectures on Elliptic Boundary Value Problems, Van Nostrand Company, New York (1965).
2. S. Agmon, A. Douglis, and L. Nirenberg, “Estimates near the boundary for solutions of elliptic partial differential equations satisfying general boundary conditions. I,” Comm. Pure Appl. Math., 12, 623–727 (1959).
3. M. S. Agranovich and M. P. Vishik, “Elliptic problems with parameter and parabolic problems of the general form,” Usp. Mat. Nauk, 19, No. 3, 53–161 (1964).
4. Yu. E. Anikonov and Yu. Ya. Belov, “Determining two unknown coefficients of parabolic-type equation,” J. Inverse Ill-Posed Probl., 9, No. 5, 469–488 (2001).
5. S. N. Baranov and Yu. Ya. Belov, “On the identification problem of two unknown coefficients with inhomogeneous overdetermination conditions,” in: Nonclassical Equations of Mathematical Physics [in Russian], Insitute of Mathematics, Siberian Department of Russian Academy of Sciences, Novosibirsk (2002), pp. 11–22.