2 citations to https://www.mathnet.ru/rus/zvmmf11251

1. G. Migliaccio, H. A. Matevossian, “Steklov–Farwig Biharmonic Problem in Exterior Domains”, Lobachevskii J Math, 44:6 (2023), 2413  
2. Giovanni Migliaccio, Hovik A. Matevossian, “Mixed Biharmonic Problem with the Steklov-type and Neumann Boundary Conditions in Unbounded Domains”, Lobachevskii J Math, 43:11 (2022), 3222