LUUKKAINEN, Jouni. Approximating continous maps of metric spaces into manifolds by embeddings. Mathematica Scandinavica, Berkeley, CA, United States, v. 49, p. 61–85, 1981. DOI: 10.7146/math.scand.a-11921. Disponível em: https://journals.msp.org/mscand/article/view/1750. Acesso em: 25 jul. 2026.