Durga Indira, N, and M Venu Gopala Rao. “Automatic Facial Expression Detection System Using Single Face Classifier”. International Journal of Engineering & Technology 7, no. 3.12 (July 20, 2018): 1144–1148. Accessed May 1, 2024. https://www.sciencepubco.com/index.php/ijet/article/view/17777.