GONÇALVES, D. L.; SPREAFICO, M. The fundamental group of the space of maps from a surface into the projective plane. MATHEMATICA SCANDINAVICA, [S. l.], v. 104, n. 2, p. 161–181, 2009. DOI: 10.7146/math.scand.a-15092. Disponível em: https://www.mscand.dk/article/view/15092. Acesso em: 4 may. 2024.