ผลประเสริฐ พ. and วิทยถาวรวงศ์ พ. 2018. The Effectiveness of the Process of Developing the Life Quality of the Elderly under the Sufficiency Economy: A Case Study Lom Kao District, Phetchabun Province. Journal of Preventive Medicine Association of Thailand. 6, 3 (Jul. 2018), 240–255.