Photipim, Mali, Valanchaya Ketbumroong, Jun Norkaew, Wararat Sungwalee, and Wasugree Chavengkun. 2020. “The Effect of the Senior Schooling Program to Increase the Happiness Level Among the Elderly Living in Muen Wai Sub-District, Mueang District, Nakhon Ratchasima Province”. HCU Journal 24 (1):98-106. https://he01.tci-thaijo.org/index.php/HCUJOURNAL/article/view/238370.