Contributions to the theory of nonlinear oscillations.  Volume II / 
Solomon Lefschetz editor. 
 - Princeton,  Princeton University Press,  c1952. 
 - v.2., 116 p. :  diagrs. ;  23 cm. 
 - Annals of mathematics studies,  29. .
 -  no. 20, etc. Annals of mathematics studies ; .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Oscillations.
<br/><br/><label>Dewey Class. No.: </label>531.3  / CON 1952