British civil airworthiness requirements, CAP 465, section G : rotorcraft  [Books]. 
Civil Aviation Authority. 
 - London  Civil Aviatiuon Authority  1982 
<br/><br/><label>ISBN: </label>0860391647  0.00 
<br/><br/><label>Dewey Class. No.: </label>TL/671.1  / CIV