Approximation by multivariate Bernstein-Durrmeyer operators and learning rates of least-squares regularized regression with multivariate polynomial kernels. - Bing-Zheng Li (J. Approx. Theory, 2013)

Approximation on variable exponent spaces by linear integral operators. - Bing-Zheng Li; Bo-Lu He; Ding-Xuan Zhou (J. Approx. Theory, 2017)