source for the margin of error of curvature

[zeebo17]

I have seen in a few places around the web that the margin of error for the flatness of the universe is about 2%, but haven't seen any citations. Could anyone refer me to a reputable paper that I could cite that mentions what this margin of error is?

Thanks!

[nicksauce]

A quick arxiv search gave me this paper from Oct 2007:

http://arxiv.org/abs/astro-ph/0703780

[Chalnoth]

You can get better constraints by adding baryon acoustic oscillation and supernova data to the WMAP result. They estimate the following parameters for w = constant:
http://lambda.gsfc.nasa.gov/product/map/current/params/owcdm_sz_lens_wmap5_bao_snall.cfm

The curvature parameter is:
-0.0175 < \Omega_k < 0.0085 (95% confidence)

...which is a significantly tighter confidence interval than is given in the above paper.

[zeebo17]

Great, thanks!