KLEPPE, J. O. Deformations of graded algebras. MATHEMATICA SCANDINAVICA, [S. l.], v. 45, p. 205–231, 1979. DOI: 10.7146/math.scand.a-11837. Disponível em: https://www.mscand.dk/article/view/11837. Acesso em: 27 apr. 2024.