LAURA BUTARBUTAR, Yenny; VIOLITA SITORUS, Nurmely. ANALISIS TATA NIAGA BIJI KOPI ROBUSTA DI KABUPATEN DAIRI. Akrab Juara : Jurnal Ilmu-ilmu Sosial, [S. l.], v. 4, n. 1, p. 176–190, 2019. Disponível em: https://akrabjuara.com/index.php/akrabjuara/article/view/449. Acesso em: 22 jan. 2026.