1. A. N. Tikhonov and V. Ya. Arsenin, Solutions of Ill-Posed Problems (Halsted, New York, 1978; Nauka, Moscow, 1978).
2. M. M. Lavrent'ev, V. G. Romanov, and S. P. Shishatskii, Ill-Posed Problems of Mathematical Physics and Analysis (Nauka, Novosibirsk, 1980
3. Am. Math. Soc., Providence, R.I., 1986).
4. H. T. Banks and K. Kunisch, Estimation Techniques for Distributed Parameter Systems (Birkhäuser, Boston, 1989).
5. V. K. Ivanov, V. V. Vasin, and V. P. Tanana, Theory of Linear Ill-Posed Problems and Its Applications (Nauka, Moscow, 1978; VSP, Utrecht, 2002).