MACHARLA BHANU KUMAR; K.KRANTHI KUMAR. Enhancing CAPTCHA based Image Authentication for E-mail ID and Password. International Journal of Computer Engineering in Research Trends, [S. l.], v. 2, n. 12, p. 1251–1256, 2015. Disponível em: https://www.ijcert.org/index.php/ijcert/article/view/408. Acesso em: 14 aug. 2026.