1. [1] S. Bodine and D. A. Lutz, Asymptotic integration of differential and difference equations, Lecture Notes in Mathematics 2129, Springer, 2015.
2. [2] E. A. Coddington and N. Levinson, Theory of ordinary differential equations, McGraw-Hill, New York, 1955.
3. [3] M. S. P. Eastham, “The asymptotic solutions of linear differential systems”, Mathematika 32:1 (1985), 131–138.
4. [4] M. S. P. Eastham, The asymptotic solution of linear differential systems. Applications of the Levinson theorem, London Math. Soc. Monographs. New Series 4, Oxford Science Publ., The Clarendon Press, Oxford Univ. Press, New York, 1989.
5. [5] A. S. A. Al-Hammadi, “Asymptotic theory for third-order differential equations of Euler type”, Results Math. 17:1-2 (1990), 1–14.