2 citations to https://www.mathnet.ru/eng/vmumm876

1. R. Ch. Kulaev, A. A. Urtaeva, “Sturm Separation Theorems for a Fourth-Order Equation on a Graph”, Math. Notes, 111:6 (2022), 977–981        
2. J. Ben Amara, A. A. Vladimirov, A. A. Shkalikov, “Spectral and Oscillatory Properties of a Linear Pencil of Fourth-Order Differential Operators”, Math. Notes, 94:1 (2013), 49–59