Sirisatianwattana, Paichayon, and Charuntorn Kongin. 2022. “Algorithm for Calculating the Number of Derivations on Chain Lattice”. Journal of Science and Technology CRRU 1 (2). Chiangrai, Thailand:27-37. https://li01.tci-thaijo.org/index.php/jstcrru/article/view/256177.