1. T. S. Chihara, An Introduction to Orthogonal Polynomials, Gordon and Breach (New York, 1978)
2. P. A. Clarkson, D. Gómez-Ullate, Y. Grandati, and R. Milson, Rational solutions of higher order Painlevé systems. I,
arXiv:1811.09274
(2018)
3. Durán, A.J.: Higher order recurrence relation for exceptional Charlier, Meixner, Hermite and Laguerre orthogonal polynomials. Integral Transforms Spec. Funct. 26, 357–376 (2015)
4. R. H. Fowler, Some results on the form near infinity of real continuous solutions of a certain type of second order differential equation, Proc. London Math. Soc., (1914), 341–371
5. M. Á. García-Ferrero, D. Gómez-Ullate and R. Milson, A Bochner type classification theorem for exceptional orthogonal polynomials, J. Math. Anal. Appl. (to appear),
arXiv:1603.04358