1. D. Adam, A. Felgenhaner, II.-C. Roos, M. Stynes, A nonconforming finite clement method for a singularly perturbed boundary value problem, technical report, University College Cork, Ireland, 1992.
2. D. Adam, H.-C. Roos, A nonconforming exponentially fitted finite element method 1: The interpolation error, report MATH-NM-06–1993, Technical University Dresden, 1993.
3. D. Adam, A.Felgenhauer, H.-G. Roos, A nonconforming exponentially fitted finite element method II: The discretization error, report MATH-NM-14–1993, Technical University Dresden, 1993.
4. E. Gartland Jr., An analysis of a uniformly convergent finite difference/finite element scheme for a model singular-perturbation problem Math. Comp. 51, 1988, 99–106.
5. K.Glasshoff, B.Werner, Inverse Monotonicity of Monotone L-Operators with Applications to Quasilinear and Free Boundary Value Problems,J. Math. Anal. Appl. 72, 1979, 89–105