On the asymptotic exactness of error estimators for linear triangular finite elements. R. Durán; M.A. Muschietti; ... — 1991 Numerische Mathematik
A posteriori error estimators for nonconforming finite element methods E. Dari; R. Duran; C. Padra; V. Vampa — 1996 ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique
Mixed Finite Elements for Second Order Elliptic Problems in Three Variables. F. Brezzi; J., Jr. Douglas; R. Durán — 1987 Numerische Mathematik