Bivariate-Schurer-Stancu operators based on (p;q)-integers
  The aim of this article is to introduce a bivariate extension of Shurer-Stancu operators based on (p q)integers. We prove uniform approximation by means of Bohman Korovkin type theorem rate of convergence using total modulus of smoothness and degree of approximation by using second order modulus of smoothness Peetres K functional Lipschitz type class. 
Abdul Wafi and Nadeem Rao
math.CA