1. M. Bronstein, “Computer Algebra Algorithms for Linear Ordinary Differential and Difference Equations,” in Progress in Mathematics (Birkhauser, Basel, 2001), Vol. 202, pp. 105–119.
2. M. F. Singer and M. van der Put, Galois Theory of Linear Differential Equations, Ser. Grundlehren der mathematischen Wissenschaften (Springer, Heidelberg, 2003), Vol. 328.
3. E. A. Coddington and N. Levinson, Theory of Ordinary Differential Equations (McGraw-Hill, New York, 1955; Inostrannaya Literatura, Moscow, 1958).
4. M. A. Barkatou and E. Pfluegel, “An Algorithm Computing the Regular Formal Solutions of a System Linear of Differential Equations,” J. Symbolic Comput. 28, 569–587 (1999).
5. Lect. Notes in Comput. Science;S. A. Abramov,2005