GANELIUS, Tord; FREUD, GÉza. Some remarks on one-sided approximation. MATHEMATICA SCANDINAVICA, [S. l.], v. 5, p. 276–284, 1957. DOI: 10.7146/math.scand.a-10506. Disponível em: https://tidsskrift.dk/math/article/view/10506. Acesso em: 14 aug. 2026.