Pathumnakul, Ph.D., S., M. chaibenjapol, M. Arbsuwan, and M. W. Suwanapichon. “An algorithm to assign storage areas of products for minimizing mean flow time of pick up trucks”. Engineering and Applied Science Research, vol. 29, no. 1-2, Feb. 2013, pp. 147-60, https://ph01.tci-thaijo.org/index.php/easr/article/view/6531.