BRENKEN, Berndt. Topological quivers as multiplicity free relations. MATHEMATICA SCANDINAVICA, [S. l.], v. 106, n. 2, p. 217–242, 2010. DOI: 10.7146/math.scand.a-15134. Disponível em: https://tidsskrift.dk/math/article/view/15134. Acesso em: 14 aug. 2026.