_id,doi,title
12145,10.1134/S1560354722050021,On some invariants of Birkhoff billiards under conjugacy
8689,10.1134/S1560354721010044,V.I. Arnold's ''Global'' KAM theorem and geometric measure estimates
8426,10.1134/s1560354718010057,Nonisometric domains with the same Marvizi-Melrose invariants