Lubis, D. F. ., Hernoko, A. Y. ., Purba, H. ., & Harianto, D. . (2025). When public interest meets private profit: The principle of proportionality in Indonesian PPP contracts. International Journal of Innovative Research and Scientific Studies, 8(7), 185–193. https://doi.org/10.53894/ijirss.v8i7.10424