Perturbation methods for differential equations  
Shivamoggi, Bhimsen K. 
 - Boston :  Birkhäuser,  2003 
 - xiv, 354 p. :  ill. ;  24 cm. 
<br/><br/><label>ISBN: </label>0817641890 (alk. paper) | 3764341890 (alk. paper)