1. Efficient Numerical Treatment of Periodic Systems with Application to Stability Problem;Friedman;Int. J. Numer. Methods Engng,1977
2. Formulation and Solution of Rotary-Wing Aeroelastic Stability and Response Problems;Friedman;Vertica,1983
3. Theory of Ordinary Differential Equations;Coddington,1955
4. Applied Mathematics for Engineers and Physicists;Pipes,1970
5. Linear Systems of Ordinary Differential Equations with Periodic and Quasi-Periodic Coefficients;Erugin,1966