1. Foundations of the theory of λ-zones of stability of a canonical system of linear differential equations with periodic coefficients;Krein,1955
2. Foundations of the theory of 𝜆-zones of stability of a canonical system of linear differential equations with periodic coefficients
3. Linear Differential Equations with Periodic Coefficients, Part I and II;Yakubovich,1975
4. Lyapunov inequalities for differential and difference equations;Cheng;Fasc. Math.,1991
5. Discrete linear Hamiltonian systems: A survey;Agarwal;Dynam. Systems Appl.,1999