Balser, Werner <br/><br/>
Formal Power Series & Linear Systems of Meromorphic Ordinary Differential Equations   

 -  Springer-Verlag New York, Incorporated  1999. 
 - 318 Pages 
<br/><br/><label>ISBN: </label>0387225986 
<br/><br/><label>Dewey Class. No.: </label>515/.2432  /