WINTNER, A. On the comparison theorem of Kneser-Hille. MATHEMATICA SCANDINAVICA, [S. l.], v. 5, p. 255–260, 1957. DOI: 10.7146/math.scand.a-10502. Disponível em: https://www.mscand.dk/article/view/10502. Acesso em: 5 may. 2024.