HILTON, A. J. On Steiner and Similar Triple Systems. MATHEMATICA SCANDINAVICA, [S. l.], v. 24, p. 208–216, 1969. DOI: 10.7146/math.scand.a-10931. Disponível em: https://www.mscand.dk/article/view/10931. Acesso em: 4 may. 2024.