HUNEKE, C.; JORGENSEN, D. A. Symmetry in the vanishing of Ext over Gorenstein rings. MATHEMATICA SCANDINAVICA, [S. l.], v. 93, n. 2, p. 161–184, 2003. DOI: 10.7146/math.scand.a-14418. Disponível em: https://www.mscand.dk/article/view/14418. Acesso em: 30 apr. 2024.