Kumpera A <br/><br/>
Systems of linear partial differential equations and deformation of pseudogroup structures 

 - Canada  Les Presses de L'Universite da Montreal      1974 
 - 100p.  cm. 
<br/><br/><label>Standard No.: </label>23037 
<br/><br/><label>Source: </label> Textual 
<br/><br/><label>Dewey Class. No.: </label>B334,1, L4