Spangenberg, Karl R.  <br/><br/>
Vacuum tubes / 
Karl R. Spangenberg. 
 - New York :  McGraw-hill book company,  c 1948. 
 - xvii, 860 p. :  ill. ;  22 cm. 
<br/><br/> Includes index. 
<br/><br/>340  340 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Vacuum-tubes.
<br/><br/><label>Dewey Class. No.: </label>621.381512 / S23v