1. Abdeljawad, T.: On conformable fractional calculus. J. Comput. Appl. Math. 279, 57–66 (2015)
2. Anastassiou, G.A.: Korovkin inequalities for stochastic processes. J. Math. Anal. Appl. 157(2), 366–384 (1991)
3. Anastassiou, G.A.: Moments in Probability and Approximation Theory. Pitman/Longman, # 287, UK (1993)
4. Anastassiou, G.: Quantitative Approximations. Chapman & Hall/CRC, Boca Raton (2001)
5. Anastassiou, G.: Stochastic Korovkin theory given quantitatively, Facta Universitatis (Nis). Ser. Math. Inform. 22(1), 43–60 (2007)