On Poincaré's perturbation theorem and a theorem of W. S. Loud

<i>Theory of Ordinary Differential Equations</i>

Earl A. Coddington, Norman Levinson, T. Teichmann · Physics Today · 1956 · 6.3K citations

Natural Sciences, Mathematics, Differential Equations +6

Theory of ordinary differential equations

H.L. Platzer · Journal of the Franklin Institute · 1956 · 5.7K citations

Natural Sciences, Mathematics, Differential Equations +7

A note on periodic solutions of second order differential equations without damping

George Seifert · Proceedings of the American Mathematical Society · 1959 · 21 citations · Full text

Natural Sciences, Mathematics, Differential Equations +13