Quick review. Ensures that LDMs turn up in the references. This includes SRD, OSS and the like. Requires an up to date lsst-texmf.

Basically trivial comments:

• Do we really want the bibliography style to be called gaia_aa? I don't really object to that, but it seems pretty confusing for that to be the LSST standard. (Plus I can't actually see any documentation of what the "LiveLink" stuff is all about, but I didn't look very hard).
• Does every instance of "DPDD", "SRD" etc really deserve to be a hyperlink? I'm comparing it to e.g. the Wikipedia guidelines — "Generally, a link should appear only once in an article, but if helpful for readers, a link may be repeated in infoboxes, tables, image captions, footnotes, hatnotes ...". Obviously, this document is longer than the typical Wikipedia article, but multiple links to the DPDD in a single paragraph feels excessive.
• (Pet peeve, so feel free to ignore —) do you really want to rely on xspace to get the spacing right? It always feels flakey to me (although I've not spotted any problems in this document).

Thank you. All excellent points.

• There is a lot of Gaia cruft in lsst-texmf. I'll copy this style file and rename it so we can "own" it and avoid confusion. I won't remove the original for a while since some documents rely on it.
• Also, I have been worrying about "LiveLink". That's what Gaia used. I think it would make things much clearer if we were to use "DocuShare" instead.
• I guess I'm being lazy. I don't want to have to track changes in content in the future to ensure that we have only one link at first mention. Global search and replacement for consistency was easy.
• xspace seems to be the standard for the class file. I haven't really looked at it much and I don't think these changes include xspace.

Re xspace, just to explain my concern (and how it relates to these changes) —

If you don't use xspace, you'd need to write e.g.

\DPDD{}

to stop the macro from swallowing the space after it. If you do use xspace, you can get away with writing

\DPDD

most of the time, but will then be taken by surprise when it doesn't work for obscure reasons.

I really don't think this is a big deal, though.

Merged following discussion with John Swinbank.