Approximating clique is almost NP-complete
Efficient probabilistically checkable proofs and applications to approximations
[1991] Proceedings 32nd Annual Symposium of Foundations of Computer Science
Proceedings of the twenty-fifth annual ACM symposium on Theory of computing - STOC ’93
C. Lund
M. Szegedy
L. Lovasz
M. Bellare
U. Feige
A. Russeli
Two prover protocols
Polynomial time approximation schemes for Euclidean traveling salesman and other geometric problems