1. Hastad's 3-bit PCP and hardness of max-3sat: Notes of Subhash Khot Link

2. Hardness of Minimum distance of code: Link

3. Hardness of edge-disjoint path: Link

4. Asymmetric k-center hardness: Link

5. Inapproximability of Hypergraph Vertex Cover: Link

6. Hardness of priority Steiner tree: Link1 and Link2

7. Hardness of machine minimization problem: Link

8. Hardness of buy at bulk network design: Link

9. UGC: Link