Birkhoff, Garrett  <br/><br/>
Ordinary differential equations 
/ by Garrett Birkhoff & Gian-Carlo Rota 
 - 4th ed. 
 - new york  John wiley & sons  1989 
 - 399p. 
<br/><br/><label>Dewey Class. No.: </label>515.352  / BIR/O