Reyes, A. R. L., Festijo, E. D., & Medina, R. P. (2019). Enhanced Multi-factor Out-of-Band Authentication En Route to Securing SMS-based OTP Ariel. International Journal of Engineering and Technology Innovation, 9(2), 145–154. Retrieved from https://ojs.imeti.org/index.php/IJETI/article/view/3394