Prastyo, C. E., & Sari, D. M. (2026). Challenges of Sustainability of Employer-Based Retirement Healthcare Services in Indonesia: A Longitudinal Analysis of Demographic Transition and Healthcare Costs 2019–2023. Jurnal Ilmiah Kesehatan, 18(1), 238 – 249. https://doi.org/10.37012/jik.v18i1.3714