WEIBULL, Thomas. A natural map from the ext Künneth sequence to the Tor one. MATHEMATICA SCANDINAVICA, [S. l.], v. 53, p. 203–206, 1983. DOI: 10.7146/math.scand.a-12027. Disponível em: https://tidsskrift.dk/math/article/view/12027. Acesso em: 14 aug. 2026.