Nizeyumukiza, E., A. C. Pierewan, E. Ndayambaje, and Y. Ayriza. “Social Engagement and Retirement Satisfaction: Evidence from Indonesia”. Journal of Population and Social Studies [JPSS], vol. 28, no. 3, Apr. 2020, pp. 221-3, https://so03.tci-thaijo.org/index.php/jpss/article/view/227699.