Amelia D, Zhafira AA, Ginzel BGC, Putra FY, Wibawa YS. Analyzing the Influence of Gross Domestic Product on the Human Development Index Worldwide in 2021 Using a Nonparametric Regression Approach Based on Penalized Spline Estimator. IJCSAM [Internet]. 2025 Dec. 15 [cited 2026 Jan. 30];11(2):68-75. Available from: https://journal.its.ac.id/index.php/ijcsam/article/view/8851