I would strongly argue that we need far, far *less* references than the Encyclopedia Britannica due to the hypertext linking in the wikipedia.
What hypertexting means is that the references tend to get pushed down to daughter nodes on particular topics, and you end up with summary articles with few references that internally refer to other articles. In Brittanica I bet that the references are duplicated throughout the Encyclopedia giving an artificially high reference count.
We need to get away from encyclopedia envy and do the right things for the wikipedia.