1. A. N. Tikhonov and V. Ya. Arsenin, Solutions of Ill-Posed Problems (Nedra, Moscow, 1979; Wiley, Winston, NY, 1977).
2. O. A. Liskovets, Variational Methods for Solving Unstable Problems (Nauka i Tehnika, Minsk, 1981) [in Russian].
3. V. K. Ivanov, V. V. Vasin, and V. P. Tanana, Theory of Linear Ill-Posed Problems and Its Applications (Nauka, Moscow, 1978) [in Russian].
4. S. I. Kabanikhin, Inverse and Ill-Posed Problems (Sib. Nauchn. Izd., Novosibirsk, 2009) [in Russian].
5. V. V. Voevodin and Yu. A. Kuznetsov, Matrices and Computations (Nauka, Moscow, 1984) [in Russian].