What is the policy on this?
On one hand, they are technically "correct".
On the other, I do not feel that they add much to the site itself. What if the link one day goes down?
Should this answer be rewarded/picked over an answer that actually explains the answer to the question in the answer itself? One that has thought and time put into it? Possibly one that personally addresses the issues that the asker specifically raises at a finer point than the broad question? At the tone/level that the asker appears to be asking the question at?
Perhaps they should even quote some relevant parts of the paper.