Bărbosu, Dan. “The Voronovskaja Theorem for Bernstein-Schurer Bivariate Operators”. Rev. Anal. Numér. Théor. Approx. 33, no. 1 (February 1, 2004): 19–24. Accessed December 4, 2024. https://ictp.acad.ro/jnaat/journal/article/view/2004-vol33-no1-art3.