On the Hardenss of Apprximating Minimization Problems by Lund and Yannakakis, 1994 HERE

A Threshold of ln n for Approximating Set Cover by Feige, 1998 HERE

A Sub-Constant Error-Probabiity Low-Degree Test, and a Sub-Constant Error-probability PCP Charactirzation of NP by Raz and Safra, 1997, HERE

Approx Algs by Vazirani, 2001 HERE

Algorithmic Construction of Sets for k-Restrictions by Alon-Moshovitz-Safra, 2006 HERE

Analytical Approach to Parallel Repittion by Dinur and Steurer, 2013 HERE

The Projection Game Conjecture and the NP-hardness of ln n-Approximating Set-Cover, 2015 HERE