Nonlinear differential equations and nonlinear mechanics   
ed. by Joseph P. LaSalle, Solomon Lefschetz 
 - New York  Academic Press  1963 
 - xiv, 505p. 
<br/><br/><label>LCCN: </label>63-11696 
<br/><br/><label>Dewey Class. No.: </label>515.35  / N63;1