Knowles, I.W. <br/><br/>
Spectral Theory of Differential Operators 
/ by I. W. Knowles & R. T. Lewis 
 - Amsterdam  North-Holland Publishing Company  1981 
 - xv,384p. 
 - North-Holland Mathematics Studies 55 .
<br/><br/><label>ISBN: </label>0444862773 
<br/><br/><label>Dewey Class. No.: </label>515.7242  / KNO/S