Reyes, Ariel Roy L., Enrique D. Festijo, and Ruji P. Medina. “Enhanced Multi-Factor Out-of-Band Authentication En Route to Securing SMS-Based OTP Ariel”. International Journal of Engineering and Technology Innovation 9, no. 2 (April 1, 2019): 145–154. Accessed May 27, 2024. https://ojs.imeti.org/index.php/IJETI/article/view/3394.