2 citations to https://www.mathnet.ru/eng/jmp16

1. P. G. Grinevich, R. G. Novikov, “Spectral inequality for Schrödinger's equation with multipoint potential”, Russian Math. Surveys, 77:6 (2022), 1021–1028            
2. I. A. Taimanov, “The Moutard Transformation for the Davey–Stewartson II Equation and Its Geometrical Meaning”, Math. Notes, 110:5 (2021), 754–766