WAHDE, Gösta. Interpolation in Non-Quasi-Analytic Classes of Infinitely Differentiable Functions. Mathematica Scandinavica, Berkeley, CA, United States, v. 20, p. 19–31, 1967. DOI: 10.7146/math.scand.a-10815. Disponível em: https://journals.msp.org/mscand/article/view/2506. Acesso em: 25 jul. 2026.