Before revision:  These higher-order expansions also allow for the uniform kernel and any derivative order, significantly improving on previous technical results available in the literature . In addition, we discuss principled, inference-optimal tuning parameter (bandwidth) selection and kernel functions. The main methodological results obtained in this paper are implemented in companion R andStata software packages .
After revision:  These higher-order expansions also allow for the uniform kernel and any derivative order, significantly improving on previous technical results available in the literature  R andStata software packages .