Marpaung, Bintang Sahala, and Johanes Sukadi. “Studi Pengukuran Kemampulabaan Perusahaan Sektor Perdagangan, Jasa Dan Investasi”. Jurnal Ilmiah Manajemen Kesatuan 4, no. 3 (August 1, 2018): Page 131 – 143. Accessed June 15, 2026. https://jurnal.ibik.ac.id/index.php/jimkes/article/view/104.