Team, Support. 2008. “Valuation $\tau$-Semirings and Valuation $\tau$-Ideals: S. Sangwirotjanapat, S. Tipyota, S. Pianskool”. Thai Journal of Mathematics 6 (3):93-102. https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/138.