CARLSEN, T. M.; WINGER, M. L. Orbit equivalence of graphs and isomorphism of graph groupoids. MATHEMATICA SCANDINAVICA, [S. l.], v. 123, n. 2, p. 239–248, 2018. DOI: 10.7146/math.scand.a-105087. Disponível em: https://www.mscand.dk/article/view/105087. Acesso em: 24 apr. 2024.