British civil airworthiness requirements, CAP 472, section R : radio  [Books]. 
Civil Aviation Authority. 
 - London  Civil Aviatiuon Authority  1974 
<br/><br/><label>ISBN: </label>0903083396  0.00 
<br/><br/><label>Dewey Class. No.: </label>TL/671.1  / CIV