Petrovskii, I G. <br/><br/>
Ordinary differential equations/ 
I G Petrovskii. 
 - [S.l.] :  PH,  1966. 
 - x, 232 
<br/><br/><label>ISBN: </label>0486646831 
<br/><br/><label>Standard No.: </label>0486646831