Elsgolts, L. E. <br/><br/>
Differential Equations and the Calculus of Variations  

 - Moscow :   Mir Publishers,   1970 
 - 440 p. 
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<br/><br/><label>Subjects--Topical Terms: </label><br/>Differential Equations
<br/><br/><label>Dewey Class. No.: </label>515.35  / ELS