MR. MOHAMMED SHUJA UR RAHMAN; MR. MOHAMMED KHALEEL AHMED; DR. G.S.S RAO. Two Step Factor Based Authentication Control to Access Cloud Services. International Journal of Computer Engineering in Research Trends, [S. l.], v. 4, n. 10, p. 431–440, 2017. Disponível em: https://www.ijcert.org/index.php/ijcert/article/view/733. Acesso em: 30 sep. 2026.