Radio valve data 

 - London  ; Iliffe Books  , 1949 
 - 230p. 
<br/><br/><label>ISBN: </label> 9.98 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Engineering<br/>Radio Engineering
<br/><br/><label>Dewey Class. No.: </label>621.384  / RAD