Samad, R., P. J. Hoe, M. Mustafa, N. R. H. Abdullah, D. Pebrianti, and N. H. Noordin. “Comparison of Filtering Methods for Extracting Transient Facial Wrinkle Features”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 10, no. 1-2, Jan. 2018, pp. 99-104, https://jtec.utem.edu.my/jtec/article/view/3328.