ParasyukI. O. “Reduction and Coisotropic Invariant Tori of Hamiltonian Systems With Non-Poisson Commutative Symmetries. I”. Ukrains’kyi Matematychnyi Zhurnal 46, no. 5 (May 25, 1994): 537–544. Accessed November 24, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/5717.