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.

Nonisometric domains with the same Marvizi-Melrose invariants
L. Buhovsky, V. Kaloshin, Regular and Chaotic Dynamics 23 (2018) 54–59.