Reference type for open access institutional archives

I realize reference types technically are neither styles nor filters nor connections, but I still venture a question in this forum. Institutional archives may contain early versions of papers later published as journal articles (or not (currenlty) published under peer review). These early versions may have few publication data. What reference type(s) and what data would be appropriate? Example: arxiv.org/abs/1006.0928v2

– Håkon