GANELIUS, Tord. On one-sided approximation by trigonometrical polynomials. Mathematica Scandinavica, Berkeley, CA, United States, v. 4, p. 247–258, 1956. DOI: 10.7146/math.scand.a-10473. Disponível em: https://journals.msp.org/mscand/article/view/2850. Acesso em: 25 jul. 2026.