Sawatraksa, N., Lekjaroensri, C., Wetchakorn, P. and Sitong, P. (2024) “Characterization of Regularity on Elements in the Bicyclic Semigroup”, PKRU SciTech Journal, 8(2), pp. 53–64. available at: https://ph01.tci-thaijo.org/index.php/pkruscitech/article/view/257368 (accessed: 11 September 2026).