Friedrichs, Kurt O. <br/><br/>
Perturbation of spectra in Hilbert space 
<label>/ by </label> Friedrichs, Kurt O. 
 - Colorado  American Mathematical Society  1965 
 - xiii,178p.  24 cm. 
<br/><br/>SR 
<br/><br/><label>Dewey Class. No.: </label>513.82  / F