ZHANG, Yong. Approximate complementation and its applications in studying ideals of Banach algebras. Mathematica Scandinavica, Berkeley, CA, United States, v. 92, n. 2, p. 301–308, 2003. DOI: 10.7146/math.scand.a-14407. Disponível em: https://journals.msp.org/mscand/article/view/812. Acesso em: 24 jul. 2026.