1. V.G. Amel’kovič. A theorem converse to a theorem of Voronovskaya type. Teor. Funkčiĭ, Funktional Anal. i Prilozen, Vyp, 2 (1966), 67–74.
2. P. Appell and J. Kampè de Fériet. Fonctions Hypergéomtriques et Hypersphériques — Polynômes d’Hermite. Gauthier-Villars, 1926.
3. H. Berens and Y. Xu. k-moduli, moduli of smoothness, and Bernstein polynomials on a simplex. Indag. Mathem., 2 (1991), 411–421.
4. H. Berens and Y.Xu. On Bernstein-Durrmeyer polynomials with Jacobi weights. In C. K. Chui, editor, Approximation Theory and Functional Analysis, pages 25–46, Boston, 1991. Academic Press.
5. H. Berens and Y. Xu. On Bernstein-Durrmeyer polynomials with Jacobi weights: The cases p = 1 and p = ∞. In S. Baron and D. Leviatan, editors, Approximation, Interpolation, and Summation, pages 51–62, Jerusalem, 1991. Israel Mathematical Conference Proceedings, Vol. 4, Weizmann Science Press of Israel.