YAKES, C. J. Essential Spectrum and Fredholm Index for Certain Composition Operators. MATHEMATICA SCANDINAVICA, [S. l.], v. 118, n. 1, p. 152–160, 2016. DOI: 10.7146/math.scand.a-23302. Disponível em: https://www.mscand.dk/article/view/23302. Acesso em: 16 apr. 2024.