GANELIUS, Tord; FREUD, GÉza. Some remarks on one-sided approximation. Mathematica Scandinavica, Berkeley, CA, United States, v. 5, p. 276–284, 1957. DOI: 10.7146/math.scand.a-10506. Disponível em: https://journals.msp.org/mscand/article/view/2819. Acesso em: 25 jul. 2026.