Lanczos, Cornelius <br/><br/>
Linear differential operators   

 - Philadelphia  SIAM  1996 
 - xvii, 564p. Index, Appendix 
 - Classics in Applied Mathematics   v. 18 .
<br/><br/>  
<br/><br/><label>Dewey Class. No.: </label>515.72  / L252.LD