Wenming, Lu. “Pointwise Weighted Approximation of Functions With Inner Singularities by Combinations of Bernstein Operators”. Journal of Progressive Research in Mathematics 7, no. 2 (April 20, 2016): 1015-1026. Accessed April 30, 2025. http://www.scitecresearch.com/journals/index.php/jprm/article/view/485.