found
:
Dunstan, S. Challenger main battle tank, 1982-1997, 1998:
p. 10 (Challenger tank, accepted for service with the British Army in Dec. 1982)
found
:
Foss, C.F. Jane's main battle tanks, 1983:
p. 96 (Challenger main battle tank; successor to the Chieftain tank)
notfound
:
Britannica Macro.