Lapsomboondee, A., S. . Sukpaiboonwat, and A. . ratniyom. “A Comparative Study of Long Term Care for Elderly in Germany, Japan, Singapore and Thailand”. Journal of Business, Innovation and Sustainability (JBIS), vol. 15, no. 1, Apr. 2020, pp. 74-86, https://so02.tci-thaijo.org/index.php/BECJournal/article/view/196036.