UN Style Guide A-Z
W X Y Z
The UN official guide is now
available (changes from 1984 are marked with *):
I didn't find anything in the UN manual about this but WHO has some recommendations: "Article, book and journal titles in references need not [my italics] be capitalized, e.g. Social science and medicine, except when they contain the name of an association or organization, e.g. Bulletin of the Pan American Health Organization, Journal of the American Medical Association " (WHO:8). See my titles article for a longer discussion of the problems.
The latest U.N. manual says: In United Nations texts, the word “ton” normally refers to metric tons (1,000 kg or 2,204.6 lb). If, however, the references to tons are to long tons (2,240 lb) or to short tons (2,000 lb), or if there is any possibility of confusion, the meaning should be specified in an explanatory note or in a footnote.
You may want to stick with tonnes, which clearly indicates metric tons, when you can. The U.N. rule seems to me to be a recipe for confusion. Brits and Americans and the rest of the Anglo-Saxon world would assume these are long tons or ask themselves what was meant.
two-thirds (adj.), two thirds (noun)
preferred by SOED, but it notes tradeable
as a variant, which I prefer.