Double citing of SDSS

[timj]

On page 7 section 4 we cite "SDSS (York et al)" and then towards the bottom of the page we say "SDSS (Abazajian et al. 2009)". Seems weird to do that. I think I'd prefer either we drop the second or we add it to the first mention.

[mjuric]

Good points, but I'm my solution will just make it worse :).

• The first reference is in the context of the technical design + plan of the survey, so York is most appropriate
• The second time I cite it I specifically refer to DR7 so Abazajian et al. is appropriate
• And the third time I mention it, I refer to it in the context of the imaging data we used for reprocessing, so actually the DR9 paper (Ahn et al.) is the right one to cite there.