PARASYUK, I. O. Quasiperiodic Extremals of Nonautonomous Lagrangian Systems on Riemannian Manifolds. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 66, n. 10, p. 1387–1406, 2014. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2230. Acesso em: 27 apr. 2025.