Sofyan, D., and N. Nurhayati. “Analisis Pengaruh Debt to Equity Ratio (DER) Terhadap Return on Asset (ROA) Pada PT Semen Indonesia Tbk”. Journal of Business and Economics Research (JBE), Vol. 1, no. 3, Oct. 2020, pp. 220-5, doi:10.47065/jbe.v1i3.249.