TAFTEBERG JAKOBSEN, I. On Certain Homomorphism Properties of Graphs I. MATHEMATICA SCANDINAVICA, [S. l.], v. 31, p. 379–404, 1972. DOI: 10.7146/math.scand.a-11440. Disponível em: https://www.mscand.dk/article/view/11440. Acesso em: 28 apr. 2024.