explicit construction

Volume 5, Article 3 (pages 69-82)
Unconditional Pseudorandom Generators for Low Degree Polynomials
by Shachar Lovett
Volume 3, Article 6 (pages 103-128)
Linear Degree Extractors and the Inapproximability of Max Clique and Chromatic Number
by David Zuckerman
Volume 1, Article 8 (pages 149-176)
A Non-linear Time Lower Bound for Boolean Branching Programs
by Miklós Ajtai