Siregar, N.R.A.A. dkk. 2022. Pemodelan Harga Minyak Mentah Dunia Berdasarkan Efek Pandemi Covid-19 Dengan Estimator Penalized Spline. MUST: Journal of Mathematics Education, Science and Technology. 7, 2 (Des 2022), 152–166. DOI:https://doi.org/10.30651/must.v7i2.16377.