1. The truncation method for the solution of a class of variational inequalities;Berger, Alan E.;Rev. Fran\c{c}aise Automat. Informat. Recherche Op\'{e}rationnelle S\'{e}r.,1976
2. Numerical solution of a diffusion consumption problem with a free boundary;Berger, Alan E.;SIAM J. Numer. Anal.,1975
3. Problèmes unilatéraux;Brézis, Haïm;J. Math. Pures Appl. (9),1972
4. Travaux et Recherches Math\'{e}matiques, No. 21;Duvaut, G.,1972
5. Error estimates for the approximation of a class of variational inequalities;Falk, Richard S.;Math. Comput.,1974