Tabaranza, Georgie F., and Jocelyn P. Vilela. “ON STRONG AND WEAK HYPER KS-IDEALS OF DECOMPOSABLE HYPER KS-SEMIGROUPS”. Italian Journal of Pure and Applied Mathematics, vol. 35, Dec. 2015, pp. 233-42, https://journals.uniurb.it/index.php/ijpam/article/view/6438.