I think this suggestion comes with the question
how important are references on SO.
Citing other member’s work is important to make clear that you read/understood another coder’s work and it also strengthens your own answer.
Since this is a task that demands time searching on SO, I think adding a badge for this kind of behavior is something we should consider.
I don't know what would be the most appropriate type of badge, but it will certainly have to do with the number of references the user made on all his answers. Maybe we could count only the answers that got voted up or something like that.