The PCP Theorem
Clique
Probabilistic Checking of Proofs: A New Characterization of NP by Arora and Safra
Proof Verification and Hardness of Approximation Problems by ALMSS
Probabilistically Checkable Proofs and their Consequences for Approximation Algorithms by Hougardy, Promel, and Steger. They bring up the epsilon stuff that Vazarani says we don't need.
On unapproximable versions of NP-Complete Problems by Zuckerman
Robust PCP's of Proximity and Shorter PCP's PhD thesis by Prahladh Harsha
Probablistic Checking of Proofs and Hardness of Approximation Problems PhD thesis by Sanjeev Arora
Efficient Probabilistic Checkable Proofs and appliations to approximation by Bellare, Goldwasser, Lund, Russell
Interactive Proofs the hardness of approximatting cliques by Feige, Goldwasser, Lovasz, Safra, and Szegedy
Two Prove Protocols–Low Error at Affordable Rates by Feige and Kilian
Improved Non-approximabiity results by Bellare and Sudan
Clique is hard to approximate within n to the 1-ep by Hastad
Linear Degree Extractors and the Inapprox of Max Clique and Chrom Numb by Zuckerman
On the complexity of approximating the independent set problem by Berman and Schnitger
Free bits, PCPs, and non-approximability-Towards Tight Results by Bellare, Goldreich, Sudan
Approx Alg by Vazarani 2001
Dinur's Easier Proof of PCP, other papers without approx in them.
The PCP Theorem by Gap Amplification by Irit Dinur
On Dinur's Proof of the PCP theorem by Jaikumar Radhakrishnan and Madhu Sudan
Robust Characterization of Polynomials with Applications to Program Testing by Rubenfeld and Sudan
Set Cover
Two Prover One Round Proof Systems: Their Power and Their Problems by Feige and Lovasz, 1992
Efficient Probabilistic Checkable Proofs and appliations to approximation by Bellare, Goldwasser, Lund, Russell, 1993
On the Hardenss of Approximating Minimization Problems by Lund and Yannakakis, 1994
Improved low degree testing by Arora and Sudan, 1997
A Sub-Constant Error-Prob Low-Degree Test, and a Sub-Constant Error-probPCP Char of NP by Raz and Safra, 1997
A Threshold of ln n for Approximating Set Cover by Feige, 1998
Approx Alg BOOK by Vazarani 2001
Alg Construction of Sets for k-Restrictions by Alon-Moshovitz-Safra, 2006
Analytical Approach to Parallel Repition by Dinur and Steurer, 2013
The Proj Game Conj and the NP-hardness of ln n-Approx Set-Cover by Moshkovitz, 2015
VC (Vertex Cover)
Some Optimal Non-Approx results by Hastad. Inapprox for Max Cut and VC
On the hardness of approximating minimum vertex cover by Dinur and Safra
MAX3SAT
Efficient Probabilistic Checkable Proofs and appliations to approximation by Bellare, Goldwasser, Lund, Russell
Some Optimal Non-Approx results by Hastad. Inapprox for Max 3SAT
MISC
On Some Tight Inapprox Results by Berman and Karpinski. Lower bounds on approximating MAX-2SAT, E2-LIN-2, MAXCUT
LECTURE NOTES FROM WASH U
Lecture notes from Wash U