HILTON, A. J. On Steiner and Similar Triple Systems. Mathematica Scandinavica, Berkeley, CA, United States, v. 24, p. 208–216, 1969. DOI: 10.7146/math.scand.a-10931. Disponível em: https://journals.msp.org/mscand/article/view/2369. Acesso em: 25 jul. 2026.