Actually Jean-Baptiste is incorrect about those terms of use. They allow people to download the material on the website for their own personal, non-commercial use. The UN terms and conditions do not allow redistribution or compliation of the material on their website.
Actually they allow to "download and copy". I interpret this as an authorization to get and copy them.
It is true that they also forbid to "resell or redistribute" them, but I understand it as the interdiction to commercially use them. Not the interdiction to copy them for third parties because it would be otherwise contradictory with authorizing people to copy them.
This seems to make sense given the current applications of these terms of use by people on Internet.