ผลประเสริฐ พ. and วิทยถาวรวงศ์ พ., “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”, JPMAT, vol. 6, no. 3, pp. 240–255, Jul. 2018.