Zainudin, M. N. S., M. N. Sulaiman, N. Mustapha, and T. Perumal. “Pairwise Classification Using Combination of Statistical Descriptors With Spectral Analysis Features for Recognizing Walking Activities”. Journal of Telecommunication, Electronic and Computer Engineering (JTEC), vol. 9, no. 2-11, Sept. 2017, pp. 55-60, https://jtec.utem.edu.my/jtec/article/view/2738.