DAVYDENKO, A. A. On One Method for the Introduction of Local Coordinates in a Neighborhood of an Invariant Toroidal Set. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 54, n. 10, p. 1336–1347, 2002. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4172. Acesso em: 6 dec. 2025.