Are all classical superintegrable systems in two-dimensional space   linearizable?
  Several examples of classical superintegrable systems in two-dimensional spac are shown to possess hidden symmetries leading to their linearization. They are those determined 50 years ago in [Phys. Lett. 13, 354 (1965)], and the more recent Tremblay-Turbiner-Winternitz system [J. Phys. A: Math. Theor. 42, 242001 (2009)].   We conjecture that all classical superintegrable systems in two-dimensional space have hidden symmetries that make them linearizable. 
G. Gubbiotti and M.C. Nucci
nlin.SI math-ph math.MP