Elsgolts L. Differential equations and the calculus of variations

Translated from the Russian by George Yankovsky. — Moscow: Mir publishers, 1977. — 450 p.The subject of this book is the theory of differential equations and the calculus of variations. It is based on a course of lectures which the author delivered for a number of years at the Physics Department of the Lomonosov State University of Moscow.Differential equations
First-Order Differential Equations
Differential Equations of the Second Order and Higher
Systems of Differential Equations
Theory of Stability
First-Order Partial Differential EquationsThe calculus of variations
The Method of Variations in Problems with Fixed Boundaries
Variational Problems with Moving Boundaries and Certain Other Problems
Sufficient Conditions for an Extremum
Variational Problems Involving a Conditional Extremum
Direct Methods in Variational Problems