1. AERE Computer Science and Systems Division, Harwell Subroutine Library — A Catalogue of Subroutines, (AERE Harwell, UK, 1984).
2. J. Bechlars — R. Buhtz, GKS in der Praxis (Springer-Verlag, Berlin — New York, 1986).
3. R.F. Boisvert — R.A. Sweet, Mathematical Software for Elliptic Boundary Value Problems, in: W.R. Cowell, Ed., Sources and Development of Mathematical Software (Prentice-Hall, Englewood-Cliffs, 1984) 200–263.
4. C.A. Brebbia, Ed., Finite Element Systems — A Handbook (Springer-Verlag, Berlin — New York, 1983).
5. T.F. Chan — F. Saied, A Comparison of Elliptic Solvers for General Two-Dimensional Regions, SIAM J. Sci. Stat. Comput. 6 (1985) 742–760.