Frisnoiry, S., Amanda, D., Natalia, D., br. Saragih, G. L., & Sidabutar, P. (2024). Analisis Efektivitas Sempoa Sebagai Alat Hitung Kuno di Era Modern. Innovative: Journal Of Social Science Research, 4(6), 5042–5050. https://doi.org/10.31004/innovative.v4i6.17083