MAGNUS, Robert. A splitting lemma for non-reflexive Banach spaces. Mathematica Scandinavica, Berkeley, CA, United States, v. 46, p. 118–128, 1980. DOI: 10.7146/math.scand.a-11856. Disponível em: https://journals.msp.org/mscand/article/view/1791. Acesso em: 25 jul. 2026.