C. Young-Chool, J. Sang-Hyeon, L. Gyutae, L. Sangyup, K. Sangkun, and Y. Sungho, “Explaining OECD Fertility Divergence: Clustering and Machine Learning Insights”, Seminars in Medical Writing and Education, vol. 4, p. 432, Aug. 2025, doi: 10.56294/mw2025432.