SCHMIDT, Asmus L. Approximation Theorems of Borel and Fujiwara. Mathematica Scandinavica, Berkeley, CA, United States, v. 14, p. 35–38, 1964. DOI: 10.7146/math.scand.a-10703. Disponível em: https://journals.msp.org/mscand/article/view/2601. Acesso em: 25 jul. 2026.