Kubichka, A.A. and Parasyuk, I.O. (2001) “Bifurcation of a Whitney-Smooth Family of Coisotropic Invariant Tori of a Hamiltonian System under Small Deformations of a Symplectic Structure”, Ukrains’kyi Matematychnyi Zhurnal, 53(5), pp. 610–624. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/4284 (Accessed: 26 April 2025).