Kostova, V. At. “An Exact Estimate for the Approximation of the Function Msgn(A-X) With Bernstein Polynomials in Hausdorff Metric”. Anal. Numér. Théor. Approx. 19, no. 2 (August 1, 1990): 143–150. Accessed July 3, 2024. https://ictp.acad.ro/jnaat/journal/article/view/1990-vol19-no2-art8.