Tidy up references (etc)

[JeanTate]

• consistency, e.g. "in preparation", or "in prep.", or ...
• "ArXiv e-prints": if they are published, give ref; if not, give arXiv name (if no arXiv doc, replace with "in prep."), applies to refs# 6, 35, 45, 65, 78, and 80
• is "in press" acceptable? Especially as it's supposed to be 2010! Ref#17
• "Zooniverse Letters"? Search engines can't find such a thing, and you do not give a URL

I count ~eight "in prep." (and similar), though some may be referencing the same unpublished document. That's ~10% of the number of unique References. Perhaps this points to a feature of CS in astronomy that you don't mention; namely, that your review is already considerably outdated (because you rely primarily on "the astronomical literature"). By the time you have published papers to refer to, the CS project may have been going for several years, so the future you refer to in Section 7 may already have been happening (and indeed it has, or is; Radio Galaxy Zoo, for example).

[drphilmarshall]

I guess the high number of "in prep" refs is somehow reflective of the pace of the field. A small number of them will get upgraded to arxiv citations while the paper is being reviewed by the editors - and they may also ask us to remove some of them. We'll see.