1. Aydin, D.: On complex q-Szász-Mirakjan operators. Commun. Fac. Sci. Univ. Ankara. Sér. A1 Math. Stat. 61(2), 51–66 (2012)
2. Baskakov, V.A.: An example of a sequence of linear positive operators in the space of continuous functions (Russian). Dokl. Akad. Nauk SSSR. 113, 249–251 (1957)
3. Cetin, N., Ispir, N.: Approximation by complex modified Szász-Mirakjan operators. Stud. Sci. Math. Hung. 50(3), 355–372 (2013)
4. Dressel, F.G., Gergen, J.J., Purcell, W.H.: Convergence of extended Bernstein polynomials in the complex plane. Pac. J. Math. 13(4), 1171–1180 (1963)
5. Favard, J.: Sur les multiplicateurs d’interpolation. J. Math. Pures Appl. 23, 219–247 (1944)