Gonska, Heinz H., and Ding-Xuan Zhou. “Using Wavelets for Szász-Type Operators”. Rev. Anal. Numér. Théor. Approx. 24, no. 1 (August 1, 1995): 131–145. Accessed April 14, 2025. https://ictp.acad.ro/jnaat/journal/article/view/1995-vol24-nos1-2-art14.