H`A, H. T. .; KEIPER, G.; MAHMOOD, H.; O’ROURKE, J. L. . Density of $f$-ideals and $f$-ideals in mixed small degrees. MATHEMATICA SCANDINAVICA, [S. l.], v. 128, n. 1, 2022. DOI: 10.7146/math.scand.a-129244. Disponível em: https://www.mscand.dk/article/view/129244. Acesso em: 27 may. 2022.