1. U. Abel, V. Gupta, M. Ivan, On the rate of convergence of Baskakov-Kantorovich-Bézier operators for bounded variation functions. Rev. Anal. Numér. Théor. Approx. 31(2), 123–133 (2002)
2. U. Abel, M. Heilmann, V. Kushnirevych, Convergence of linking Baskakov-type operators. Periodica Math. Hungarica 80, 280–288 (2020)
3. U. Abel, M. Ivan, Some identities for the operator of Bleimann, Butzer and Hahn involving divided differences. Calcolo 36, 143–160 (1999)
4. U. Abel, M. Ivan, On a generalization of an approximation operator defined by A. Lupaş. Gen. Math. 15(1), 21–34 (2007)
5. J.A. Adell, F.G. Badía, J. de la Cal, On the iterates of some Bernstein-type operators. J. Math. Anal. Appl. 209, 529–541 (1997)