Ningsih, E. L., Mahmuda, S., & Hayati, M. N. (2025). Clustering Regency in Kalimantan Island Based on People’s Welfare Indicators Using Ward’s Algorithm with Principal Component Analysis Optimization. International Journal of Engineering and Computer Science Applications (IJECSA), 4(2), 121-134. https://doi.org/10.30812/ijecsa.v4i2.5363