JENSEN, Chr. U. Homological Dimensions of $\aleph_0$-Coherent Rings. Mathematica Scandinavica, Berkeley, CA, United States, v. 20, p. 55–60, 1967. DOI: 10.7146/math.scand.a-10819. Disponível em: https://journals.msp.org/mscand/article/view/2507. Acesso em: 25 jul. 2026.