Adji Achmad Rinaldo Fernandes, Diah Ayu Widiastuti, Nurjannah. 2020. “Smoothing Spline Semiparametric Regression Model Assumption Using PWLS Approach ”. International Journal of Advanced Science and Technology 29 (04), 2059 -70. http://sersc.org/journals/index.php/IJAST/article/view/9138.