R. . Mainggal and Y. D. Himran, “Analisis Tingkat Ketimpangan Ekonomi Kabupaten Banggai Kepulauan Menurut Willamson Index: Analysis of the Level of Economic Inequality in Banggai Islands Regency according to the Willamson Index”, Jurnal Ilmiah Produktif, vol. 8, no. 2, pp. 16–19, Nov. 2020.