1. Agmon, S.: Lectures on elliptic boundary value problems. Van Nostrand Mathematical Studies, No. 2. D. Van Nostrand Co. Inc., Princeton, N.J.-Toronto-London, 1965. Prepared for publication by B. Frank Jones, Jr. with the assistance of George W. Batten, Jr. (1965)
2. Arnold, D.N.: An interior penalty finite element method with discontinuous elements. SIAM J. Numer. Anal. 19(4), 742–760 (1982)
3. Barrios, T.P., Behrens, E.M., Bustinza, R.: A stabilized mixed method applied to Stokes system with nonhomogeneous source terms: the stationary case. Dedicated to Prof. R. Rodríguez, on the occasion of his 65th birthday. Internat. J. Numer. Methods Fluids 92(6), 509–527 (2020)
4. Barrios, T.P., Behrens, E.M., González, M.: Low cost a posteriori error estimators for an augmented mixed FEM in linear elasticity. Appl. Numer Math. 84, 46–65 (2014)
5. Barrios, T.P., Bustinza, R., Campos, C.: A note on a posteriori error estimate for dual mixed method. Departamento de Ingeniería Matemática. Universidad de Concepción, Chile, Pre-print 2020-08 (2020)