Golshan, H., and A. Farajzadeh. “ON GENERALIZED VARIATIONAL INEQUALITY PROBLEMS”. Journal of Nonlinear Analysis and Optimization: Theory & Applications, vol. 2, no. 1, Dec. 2011, pp. 1-10, http://www.math.sci.nu.ac.th/ojs302/index.php/jnao/article/view/10.