Maximum norm error estimates in the finite element method with isoparametric quadratic elements and numerical integration L. B. Wahlbin — 1978 ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique
On pointwise stability of cubic smoothing splines with nonuniform sampling points R. S. Anderssen; F. R. de Hoog; L. B. Wahlbin — 1991 ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique