MODEL GRAVITASI EKONOMI SPASIAL WILAYAH SUMATERA. JURNAL ANALISIS MANAJEMEN, [S. l.], v. 7, n. 2, p. 110–121, 2021. DOI: 10.32520/jam.v7i2.1752. Disponível em: https://ejournal.unisi.ac.id/index.php/jam/article/view/1752. Acesso em: 6 oct. 2026.