Sitorus, R., and S. Suhono. “Pengaruh Harga Batubara Acua Dan Volume Penjualan Terhadap Laba Bersih”. Jurnal Ilmiah Wahana Pendidikan, Vol. 11, no. 12.C, Dec. 2025, pp. 370-9, https://jurnal.peneliti.net/index.php/JIWP/article/view/12253.