1. Bakker, M.: A note on $$C^0$$ Galerkin methods for two-point boundary problems. Numer. Math. 38, 447–453 (1982)
2. Chen, C.: Superconvergent points of Galerkin’s method for two point boundary value problems. Numer. Math. A J. Chin. Univ. 1, 73–79 (1979)
3. Chen, C.: Superconvergence of finite element solutions and their derivatives. Numer. Math. A J. Chin. Univ. 3, 118–125 (1981)
4. Chen, C.: Structure Theory of Superconvergence of Finite Elements (In Chinese). Hunan Science and Technology Press, Changsha (2001)
5. Ciarlet, P.G.: Basic error estimates for elliptic problems. Handb. Numer. Anal. 2, 17–351 (1991)