1. N. I. Akhiezer, ЛеКЦИИ П ТЕОРИИ АППРОКСИМАЦИИ, (in Russian — Lectures in the theory of approximation), Second, revised and enlarged edition Izdat. “Nauka”, Moscow 1965, 407 pp.
2. N. I. Akhiezer and B. Ya. Levin, Generalization of S. N. Bernstein’s inequality for derivatives of entire functions, (in Russian), 1960, Issledovanija po sovremennym problemam teorii funkcii kompleksnogo peremennogo pp. 111–165, Gosudarstv. Izdat. Fiz.-Mat. Lit., Moscow.
3. G. Andrews, R. Askey and R. Roy, Special Functions, Encyclopedia of Mathematics and its Applications, 71. Cambridge University Press, Cambridge, 1999, 664 pp.
4. H. Braß, Ein Beispiel zur Theorie der besten Approximation, in: Multivariate Approximation Theory, II (Oberwolfach, 1982), Internat. Ser. Numer. Math. 61, Birkhäuser, Basel-Boston, Mass. 1982, 59–67.
5. T. A. Driscoll and L. N. Trefethen, Schwarz-Christoffel Mapping, Cambridge Monographs on Applied and Computational Mathematics, 8. Cambridge University Press, Cambridge, 2002, 132 pp.