Siahaan, Makhmul Ikhsan, dan Elly Rosmaini. “Use of Classification and Regression Tree (CART) Method for Classification of Labor Force Participation Levels in Medan City in 2019”. FARABI: Jurnal Matematika dan Pendidikan Matematika 5, no. 2 (Agustus 29, 2022): 95–103. Diakses Agustus 20, 2025. http://siakad.univamedan.ac.id/ojs/index.php/JMPM/article/view/386.