JONSSON, J. On the number of Euler trails in directed graphs. MATHEMATICA SCANDINAVICA, [S. l.], v. 90, n. 2, p. 191–214, 2002. DOI: 10.7146/math.scand.a-14370. Disponível em: https://www.mscand.dk/article/view/14370. Acesso em: 29 mar. 2024.