2 citations to https://www.mathnet.ru/rus/rcd961

1. Antonio J Ureña, “Instability of closed orbits obtained by minimization*”, Nonlinearity, 35:10 (2022), 5193  
2. Sergey V Bolotin, “Symbolic dynamics near minimal hyperbolic invariant tori of Lagrangian systems”, Nonlinearity, 14:5 (2001), 1123