L p -approximation by iterative combination of Phillips operators. Gupta, Vijay; Agrawal, P.N. — 1992 Publications de l'Institut Mathématique. Nouvelle Série
On convergence of derivatives of linear combinations of modified Lupas operators. Agrawal, P.N.; Gupta, Vijay; Sahai, A. — 1989 Publications de l'Institut Mathématique. Nouvelle Série
Simultaneous approximation for the Phillips-Bézier operators. Gupta, Vijay; Agrawal, P.N.; Karsli, Harun — 2006 JIPAM. Journal of Inequalities in Pure & Applied Mathematics [electronic only]