We Are Not a Link Farm
Stack Exchange is not a search engine. By definition, the most interesting Q&A questions will not have "point me to the reference" answers; if they did, they probably should be answers folks are using a search engine to find in the first place.
While I understand the motive that drives folks to want reference links in answers, not every answer will have a canonical external reference. As a case in point, I posted an answer to a question where I was asked for a reference link. The request itself was polite and reasonable, although difficult to fulfill, given the nature of the actual question. However, I was actually pretty unhappy about the post being edited to include links which weren't really directly relevant to the answer contained in my post.
In the interests of conforming to whatever site policy is at play, I went ahead and added a link section to the post, but I strongly feel that linking just to have links isn't useful, and creates unnecessary clutter.
Important Note: I'm trying to make a broader point, and really don't want folks to get sidetracked by the specific editing history here.
Different Classes of Answers Need Different Approaches
Any stack will have different types of answers, depending on the nature of the question at hand. Some questions will have canonical answers (e.g. "See page 77 of the PMBOK.") while others require deductive or inductive reasoning for a meaningful response.
This is why we have voting. If folks make an Appeal to Authority in their posts without adequate references, by all means vote it down. However, cluttering posts with tangential links as a sort of de rigueur defense against "Says who?!" comments seems...well, insulting to both the readers (who I choose to assume are equipped with a full suite of critical thinking skills) and the writers who are attempting to provide answers, rather than a bibliography for a dissertation.
Part of the issue here is that, unlike sites like Stack Overflow where an answer (or set of answers) can be tested meaningfully against some contextual corpus, the answers on a project management stack are a bit...squishier. If your question is about the defined meetings in Scrum, there's a set of (more or less) canonical answers available. If your question is about how to apply the Scrum methodology to a given situation, then only empirical trials will suffice to "prove" the value of the answer, and I'm not sure that making appeals to external sources is useful since the sources are no more (and no less) authoritative for being external.
The Question, Restated
What's the underlying problem that we're trying to solve with an "add links to everything" policy, and what is the evidence that this policy improves answer quality in a meaningful way?