What two countries were napalm used in the period from 1980 to 1988?
return countries ;return when  was  napalm used in  #1 ;return #1 where #2 is at least 1980 ;return #1 where #2 is at most 1988 ;return #1 in  both #3 and  #4
['select', 'project', 'comparative', 'comparative', 'intersection']