Team, S. “Falling Shadow Theory Applied to UP-Algebras: Young Bae Jun, Kyoung Ja Lee, Aiyared Iampan”. Thai Journal of Mathematics, vol. 17, no. 1, Feb. 2019, pp. 1-9, https://thaijmath2.in.cmu.ac.th/index.php/thaijmath/article/view/870.