Abbreviated NTBT, this 1963 treaty was signed by the U.S., the USSR & the U.K.
It is also abbreviated as the Limited Test Ban Treaty ( LTBT ) and 
Nuclear ... Antarctica (US English , UK English or or ) is Earth 's southernmost 
continent... [DOC] [TLE] Comprehensive Test Ban Treaty - Law dictionary [PAR] Nuclear Test-Ban Treaty  an agreement signed by Britain, the Soviet Union, 
and the U.S. in 1963, committing nations to halt atmospheric tests of nuclear 
weapons: by the end of 1963, 96 additional nations had signed the treaty.