Remind me again why we do not allow reference requests? While I can see this as being "not helpful" for a particular idiosyncratic problem, for a general problem ("Best books on the Seven Years War?") answers would be useful for the general public. Is this a Stack Exchange policy, or just the policy of the site?
I guess I understand the basic motivation, which is that a reference opinion is at some level always an opinion (although I guess you could say that about any historical "consensus" as well), so there is no single answer. However, there are useful answers that have an opinion component and I guess I don't see what is wrong with having multiple answers.