Sawatraksa, N., Lekjaroensri, C., Wetchakorn, P., & Sitong, P. (2024). Characterization of Regularity on Elements in the Bicyclic Semigroup. PKRU SciTech Journal, 8(2), 53–64. retrieved from https://ph01.tci-thaijo.org/index.php/pkruscitech/article/view/257368