Kawasaki, T., Toyoda, M., & Watanabe, T. (2011). THE HAHN-BANACH THEOREM AND THE SEPARATION THEOREM IN A PARTIALLY ORDERED VECTOR SPACE. Journal of Nonlinear Analysis and Optimization: Theory & Applications, 2(1), 111-117. Retrieved from http://www.math.sci.nu.ac.th/ojs302/index.php/jnao/article/view/18