1. M. Abramowitz, I.A. Stegun (eds.), Handbook of Mathematical Functions (Dover, New York, 1965)
2. R.A. Adams (ed.), Sobolev Spaces (Academic, Amsterdam, 1975)
3. S. Agmon, Lectures on Elliptic Boundary Value Problems (van Nostrand, Princeton, NJ, 1965)
4. U.M. Ascher, R.M.M. Mattheij, R.D. Russell (eds.), Numerical Solution of Boundary Value Problems for Ordinary Differential Equations (Prentice Hall, Englewood, NJ, 1988)
5. A.K. Aziz (ed.), The Mathematical Foundations of the Finite Element Method with Applications to Partial Differential Equations (Academic, New York, 1972)