1. R. Arcangeli, Pseudo-solution de l’equation Ax = y, C.R. Acad. Sci. Paris, Ser. A, 263(1966), 282–284.
2. J. P. Butler, J. A. Reeds and S. V. Dawson, Estimating solutions of first-kind integral equations with nonnegative constraints and optimal smoothing, SIAM J. Numer. Anal. 18(1981), 381–397.
3. C. W. Groetsch, Generalized Inverses of Linear Operators: Representation and Approximation, Dekker, New York, 1977.
4. C. W. Groetsch, On a regularization-Ritz method for Fredholm equations of the first kind, J. Integral Equations 4(1982), 173–182.
5. C. W. Groetsch, On the asymptotic order of accuracy of Tikhonov regularization, J. Opt. Th. Appl., to appear.