KUSTAANHEIMO, Paul. On the relation of congruence in finite geometries. Mathematica Scandinavica, Berkeley, CA, United States, v. 5, p. 197–201, 1957. DOI: 10.7146/math.scand.a-10494. Disponível em: https://journals.msp.org/mscand/article/view/2831. Acesso em: 25 jul. 2026.