Pichelin, E. ., M. . Fortin, and S. . Boivin. “E" Tude Numerique d’estimations d’erreur a Posteriori”. European Journal of Computational Mechanics, vol. 9, no. 4, May 2000, pp. 467-86, https://journals.riverpublishers.com/index.php/EJCM/article/view/2919.