Friedrichs, K. O. <br/><br/>
Spectral theory of operators in Hilbert space  / 

 - New York:  Springer-Verlag,  1973 
 - x, 244p. 
 - Applied Mathematical Sciences ; v. 9 .
<br/><br/><label>Dewey Class. No.: </label>515.72  / F911.ST