Anastassiou, George A., and Merve Kester. “Global Smoothness and Approximation by Generalized Discrete Singular Operators”.
Rev. Anal. Numér. Théor. Approx.
, vol. 43, no. 2, Aug. 2014, pp. 113-40,
https://doi.org/10.33993/jnaat432-1024
.