ALFSEN, E. M. On a General Theory of Integration Based On Order. MATHEMATICA SCANDINAVICA, [S. l.], v. 6, p. 67–79, 1958. DOI: 10.7146/math.scand.a-10537. Disponível em: https://www.mscand.dk/article/view/10537. Acesso em: 11 apr. 2025.