On some invariants of Birkhoff billiards under conjugacy
E. Koudjinan, V. Kaloshin, Regular and Chaotic Dynamics 27 (2022) 525–537.

V.I. Arnold's ''Global'' KAM theorem and geometric measure estimates
L. Chierchia, E. Koudjinan, Regular and Chaotic Dynamics 26 (2021) 61–88.

Non co-preservation of the 1/2 and  1/(2l+1)-rational caustics along deformations of circles
V. Kaloshin, E. Koudjinan, (2021).

A KAM theorem for finitely differentiable Hamiltonian systems
E. Koudjinan, Journal of Differential Equations 269 (2020) 4720–4750.

Rigorous numerics for critical orbits in the quadratic family
A. Golmakani, E. Koudjinan, S. Luzzatto, P. Pilarczyk, Chaos 30 (2020).

V. I. Arnold’s cpointwised KAM theorem
L. Chierchia, E. Koudjinan, Regular and Chaotic Dynamics 24 (2019) 583–606.