Simbolon, Heri Yusus, Sawaluddin, and Marwan Ramli. “Quadratic Programming Approach in the Non-Negatif Matrix Factorization”. Journal of Mathematics Technology and Education 2, no. 2 (December 24, 2023): 150-156. Accessed May 16, 2024. https://talenta.usu.ac.id/jomte/article/view/15670.