2 citations to https://www.mathnet.ru/rus/mzm641

1. Bilender Allahverdiev, “Non-self-adjoint singular matrix Sturm-Liouville operators with general boundary conditions”, Filomat, 38:30 (2024), 10505  
2. Allahverdiev B.P., “Spectral Analysis of Singular Matrix-Valued Sturm-Liouville Operators”, Mediterr. J. Math., 16:4 (2019), 83