Chaisri, W., and R. . Noppanatwongsakorn. “Morale and Spirit in the Performance of Personnel of Nong Khaem District Office, Bangkok”. Dhammathas Academic Journal, vol. 22, no. 2, June 2022, pp. 153-64, https://so06.tci-thaijo.org/index.php/dhammathas/article/view/254320.