1. Phillips D, L., A technique for the numerical solution of certain integral equations of the first kind, — J. Assoc, Comput, Mach., 1962, 9, No.1, pp, 84–97.
2. Tikhonov A. N., On the solution of ill-posed problems and the method of regularization — Dokl. Akad. Nauk SSSR, 1963, 151, No.3, pp, 501–504.
3. Tikhonov A. N., On the regularization of ill-posed problems, — Dokl. Akad. Nauk SSSR, 1963, 153, No.1, pp. 45–52.
4. Twomey S., On the numerical solution of Fredholm integral equations of the first kind by the inversion of the linear system produced by quadratiere. — J. Assoc. Comput. Mach., 1963, 10, No.1.
5. Ivanov V, K., On the approximate operator equations of the first kind,-Zhurnal vychislitelnoy matematiki i matem. fiziki, 1966, 6, No.6, pp, 1089–1094.