1. and , Difference Approximations for Initial Value Problems for Partial Differential Equations, Report NR 7, Department of Computer Science, Uppsala University, Sweden, (Sept. 1967).
2. Theory of Matrices, Academic Press, New York/London 1969, p. 224.
3. Applied Linear Algebra, Prentice Hall, Inc., Englewood Cliffs, New Jersey 1969, p. 415.
4. Numerical Solution of the Korteweg-de Vries Equation, Report NR. 25, Department of Computer Science, Uppsala University, Sweden, (Oct. 1969).