Buono P.-L., Offin D.C., “Instability Criterion For Periodic Solutions With Spatio-Temporal Symmetries in Hamiltonian Systems”, J. Geom. Mech., 9:4 (2017), 439–457
Hu X., Wang P., “Hill-Type Formula and Krein-Type Trace Formula For S-Periodic Solutions in ODEs”, 36, no. 2, SI, 2016, 763–784
Hu X., Wang P., “Eigenvalue problem of Sturm–Liouville systems with separated boundary conditions”, Math. Z., 283:1-2 (2016), 339–348
Xijun Hu, Yuwei Ou, Penghui Wang, “Trace formula for linear Hamiltonian systems with its applications to elliptic Lagrangian solutions”, Arch. Ration. Mech. Anal., 216:1 (2015), 313–357
Bolotin S.V., Negrini P., “Variational approach to second species periodic solutions of Poincaré of the 3 body problem”, Discret. Contin. Dyn. Syst., 33:3 (2013), 1009–1032
E. Petrisor, “Twist number and order properties of periodic orbits”, Phys. D, 263 (2013), 57–73
М. Н. Давлетшин, “Формула Хилла для $g$-периодических траекторий лагранжевых систем”, Тр. ММО, 74, № 1, МЦНМО, М., 2013, 75–113 ; M. N. Davletshin, “Hill’s formula for $g$-periodic trajectories of Lagrangian systems”, Trans. Moscow Math. Soc., 74 (2013), 65–96
Hu Xijun, Wang Penghui, “Conditional Fredholm determinant for the $S$-periodic orbits in Hamiltonian systems”, J. Funct. Anal., 261:11 (2011), 3247–3278