1. A. N. Tikhonov, ?On the stability of inverse problems,? Dokl. Akad. Nauk SSSR,39, No. 5, 195?198 (1943).
2. M. M. Lavrent'ev, Some Ill-Posed Problems of Mathematical Physics [in Russian], Izd. Sibirsk. Otdel. Akad. Nauk SSSR (1962).
3. A. N. Tikhonov, ?On the solution of ill-posed problems and a method of regularization,? Dokl. Akad. Nauk SSSR,151, No. 3, 501?504 (1963).
4. V. K. Ivanov, ?On ill-posed problems,? Matem. Sb.,61, No. 2, 211?223 (1963).
5. T. Carleman, Les Fonctions Quasi Analytiques, Gauthier-Villars, Paris (1926).