1. Yu. I. Volkov, ?Multidimensional approximation operators, generated by Lebesgue-Stieltjes measures,? Izv. Akad. Nauk SSSR, Ser. Mat.,47, No. 3, 435?454 (1983).
2. O. Arama, ?Proprietati privind monotonia surului si aplicarea de interpolare ale lui S. N. Bernstein si aplicarea lor la studine aproximarii functiolor,? Acad. Rep. Pop. Rom., Fil. Cluj., Stud. Cerc. Mat., No. 8, 195?210 (1957).
3. A. Lupas, ?On Bernstein power series,? Mathematica,8(31), No. 2, 287?296 (1966).
4. A. Jakimovski, ?Generalized Bernstein polynomials for discontinuous and convex functions,? J. Anal. Math.,23, No. 1, 171?183 (1970).
5. Yu. I. Volkov, ?New examples of approximation positive linear operators,? in: Methods of the Theory of Approximation and Their Applications [in Russian], Inst. Mat. Akad. Nauk Ukr. SSR, Kiev (1982), pp. 10?19.