R. K. S. Rathore, Linear combinations of linear positive operators and generating relations on special functions, Ph. D. Thesis, Delhi, 1973.Search in Google Scholar
F. Sofonea, On a sequence of linear and positive operators, General Mathematics, vol. 16, no. 4, 2008, 155-165.Search in Google Scholar
P. C. Sikkema, On some linear positive operators, Indag. Math., vol. 32, 1970, 327-337.Search in Google Scholar