Davies, E.B. <br/><br/>
Spectral theory and differential operators   
by E.B. Davies 
 - Cambridge  Cambridge University Press  1995 
 - ix, 182p. 
 - Cambridge studies in advanced mathematics  42 .
<br/><br/><label>ISBN: </label>0521587107 
<br/><br/><label>Dewey Class. No.: </label>515.7242  / N95