CARVALHO, F. J. C. De; ROBERTSON, S. A. Self-parallel curves. MATHEMATICA SCANDINAVICA, [S. l.], v. 65, p. 67–74, 1989. DOI: 10.7146/math.scand.a-12266. Disponível em: https://www.mscand.dk/article/view/12266. Acesso em: 5 dec. 2025.