ZIESCHANG, Heiner. Algorithmen für einfache Kurven auf Flächen. Mathematica Scandinavica, Berkeley, CA, United States, v. 17, p. 17–40, 1965. DOI: 10.7146/math.scand.a-10761. Disponível em: https://journals.msp.org/mscand/article/view/2564. Acesso em: 25 jul. 2026.