1. H.W. Engl and R.Kress, A singular perturbation problem for linear operators with an application to electrostatic and magneto-static boundary and transmission problems, to appear.
2. H.W.Engl and M.Z. Nashed, New extremal characterizations of generalized inverses of linear operators, to appear.
3. C.W. Groetsch, Regularization of ill-posed problems, Technical Report AFFDL-TR-78–129, U.S. Air Force Flight Dynamics Laboratory, Wright-Patterson Air Force Base, Ohio 45433 (1978).
4. R.Kress, On the limiting behaviour of solutions to boundary integral equations associated with time harmonic wave equations for small frequencies, Math.Meth.Appl.Sci. 1 (1979), 89–100.
5. R.H.Moore and M.Z.Nashed, Approximations to generalized inverses of linear operators, SIAM J.Appl. Math. 27 (1974), 1–16.