Amri, Ihsan Fathoni, Nur Chamidah, Toha Saifudin, Budi Lestari, Dursun Aydin, and Febrian Rohim. “A Penalized Least Squares Estimation of Fourier Series Semiparametric Regression Theory, Simulation, and Application”. Statistics, Optimization & Information Computing 15, no. 4 (February 20, 2026): 3255-3281. Accessed April 25, 2026. http://47.88.85.238/index.php/soic/article/view/3139.