Badea, Cătălin, Ion Badea, and Heinz H. Gonska. “ Improved Estimates on Simultaneous Approximation by Bernstein Operators”. Rev. Anal. Numér. Théor. Approx. 22, no. 1 (February 1, 1993): 1–21. Accessed April 11, 2025. https://ictp.acad.ro/jnaat/journal/article/view/1993-vol22-no1-art1.