Farago, Peter Stephen. <br/><br/>
Free-electron physics 
[by] P. S. Farago. 
 - Harmondsworth,  Penguin,  1970. 
 - 269 p.  illus.  21 cm. 
 - Penguin library of physical sciences: physics  Penguin education. .
<br/><br/><label>ISBN: </label>0140800999 
<br/><br/><label>Subjects--Index Terms: </label>Electron optics.  Vacuum-tubes 
<br/><br/><label>Dewey Class. No.: </label>537.5  / FAR