1. The method of differentiating under the integral sign;Almkvist;J. Symbolic Computation,1990
2. Orthogonal polynomials and special functions;Askey,1975
3. Generalized hypergeometric series;Bailey,1935
4. Modules over a ring of differential operators, study of the fundamental solutions of equations with constant coefficients;Bernstein;Functional Analysis and Its Applications,1971
5. Rings of Differential Operators;Bjork,1979