1. Dynamic Stability of Elastic Systems;Bolotin,1964
2. Parametric Vibrations;Schmidt,1978
3. Linear Differential Equations with Periodic Coefficients and Their Applications;Yakubovich,1975
4. V.V. Bolotin, Random Vibrations of Elastic System, Martinus Nijhoff, NY, 1984.
5. R.Z. Khasminskii, The Stability of System of Differential Equations under Random Disturbance of its Parameters, Nauka, Moscow, 1969 (in Russian).