We should have no more than two of them, maybe even only one of them. Any thoughts which of those are the most useful?
I think they are all meta-tags and they should not be used.
I've used references to request scientific articles on a specific claim.
I've used resources to ask for collections of material to assist in learning more about a general topic. Based on the current discussions in Meta, all the questions tagged this way may get marked off-topic.
At the time of writing, there were no remaining questions tagged resources-references.