Cockeran, Marike, and Cornelia J. Swanepoel. “Bias and Variance Reduction Procedures in Non-Parametric Regression”. South African Statistical Journal 50, no. 1 (March 31, 2016): 123–148. Accessed April 3, 2026. https://www.journals.ac.za/index.php/sasj/article/view/5536.