Sirasuntorn, N., D. Jongjit, P. Srichai, and W. Kwanta. “Certain Cyclic Hypergroups with Property of Subhypergroup Indices”. Burapha Science Journal, vol. 29, no. 3 September-December, Sept. 2024, pp. 889-01, https://li05.tci-thaijo.org/index.php/buuscij/article/view/432.