Navansh Goel, Tejaswi Kumar, and C. Oswald. “A Novel and Efficient Multilayered Approach to CAPTCHA: Design, Performance and Usability Evaluation”. International Journal of Computer Information Systems and Industrial Management Applications 15 (January 1, 2023): 22. Accessed May 1, 2026. https://cspub-ijcisim.org/index.php/ijcisim/article/view/562.