REFERENCES
- Brunside, W. S. & Panton, A. W., The theory of equations, Vol. I, tenth edition (S. Chand & Co., Delhi).
- Cosgriff, R. L., “Application of linear differential equations with periodic coefficients in the study of non-linear phenomenon”, Automatic and Remote Control, Proceedings of the First Congress of International Federation of Automatic Control Moscow, 1960.
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- Minorsky, N., Introduction to Non-linear Mechanics, Chapter 12 (Edwards, Ann Arbour, Michigan).
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- Valeev, K. G. “On periodic differential equations”, J. Appl. Math. Mech., 24 (1960), 1493.