FRÖBERG, Ralf. An inequality for Hilbert series of graded algebras. Mathematica Scandinavica, Berkeley, CA, United States, v. 56, p. 117–144, 1985. DOI: 10.7146/math.scand.a-12092. Disponível em: https://journals.msp.org/mscand/article/view/1537. Acesso em: 25 jul. 2026.