1. Almkvist, G., Zeilberger, D. (to appear). A MAPLE program that finds, and proves, recurrences and differential equations satisfied by hyperexponential definite integrals. SIGSAM Bulletin.
2. Generalized Hypergeometric Series;Bailey,1935
3. Modules over a ring of differential operators, study of the fundamental solutions of equations with constant coefficients;Bernstein;Functional Analysis and Its Applications,1971
4. Rings of Differential Operators;Björk,1979
5. Gröbner bases—an algorithmic method in polynomial ideal theory;Buchberger,1985