Luftkrieg 1914-18: ~ns1and I 61.4-29 
Powers, Barry D.: ~)trates;Y 1.'lithout 
Dritish air strateßy 1914-1939. -
Ee1m (1976). 295 :~. 80 
slide-rule. 
Lonaon: 
Uib1ioßra~hie ~. 267-288.