Talk:CAT(k) space

I added a citation needed for the last property, because the article explains the $$\operatorname{CAT}(k)$$ property and introduces it by using the categorization by Alexandrov. I couldn't find a source for the mentioned Classification by Lott-Villani-Sturm. Kellertuer (talk) 10:11, 12 December 2013 (UTC)