1. Yu. E. Boyarintsev, Regular and Singular Systems of Linear Ordinary Differential Equations (Nauka, Novosibirsk, 1980) [in Russian].
2. V. F. Chistyakov, Algebraic-Differential Operators with Finite-Dimensional Kernel (Nauka, Novosibirsk, 1996) [in Russian].
3. L. A. Vlasenko, Evolution Models with Implicit and Singular Differential Equations (Sist. Tekhnol., Dnepropetrovsk, 2006) [in Russian].
4. R. Lamour, R. März, and C. Tischendorf, Differential-Algebraic Equations: A Projector Based Analysis (Springer, Berlin, 2013).
5. A. A. Belov, Descriptor Systems and Control Problems (Fizmatlit, Moscow, 2015) [in Russian].