MACHARLA BHANU KUMAR and K.KRANTHI KUMAR (2015) “Enhancing CAPTCHA based Image Authentication for E-mail ID and Password”, International Journal of Computer Engineering in Research Trends, 2(12), pp. 1251–1256. Available at: https://www.ijcert.org/index.php/ijcert/article/view/408 (Accessed: 15 August 2026).