Argyros, I., and S. Hilout. “ON THE SEMILOCAL CONVERGENCE OF ULM’S METHOD”. Journal of Nonlinear Analysis and Optimization: Theory & Applications, vol. 3, no. 2, Aug. 2012, pp. 215-23, http://www.math.sci.nu.ac.th/ojs302/index.php/jnao/article/view/120.