DUTTA, Sudipta, and Rima GHOSH. “Korovkin Type Approximation on an Infinite Interval via Generalized Matrix Summability Method Using Ideal”. Studia Universitatis Babeș-Bolyai Mathematica, vol. 65, no. 2, June 2020, pp. 243–254, doi:10.24193/subbmath.2020.2.06.