MAHATMA, Yudi. THE FIRST U-EXTENSION MODULE AS CLASSES OF SHORT U-EXACT SEQUENCES. Jurnal Matematika UNAND, [S. l.], v. 10, n. 4, p. 553–560, 2021. DOI: 10.25077/jmu.10.4.553-560.2021. Disponível em: https://jmua.fmipa.unand.ac.id/index.php/jmua/article/view/899. Acesso em: 5 nov. 2026.