“Study of Viola Jones Face Detection on Color Image based on Skin Pigmentation Level”. Jurnal ELEMENTER (Elektro dan Mesin Terapan) 1, no. 1 (Mei 30, 2015): 44–52. Diakses Juli 11, 2026. https://jurnal.pcr.ac.id/index.php/elementer/article/view/16.