Omer Reingold Luca Trevisan Madhur Tulsiani Salil P. Vadhan Dense Subsets of Pseudorandom Sets. 76-85 2008 FOCS http://dx.doi.org/10.1109/FOCS.2008.38 conf/focs/2008 db/conf/focs/focs2008.html#ReingoldTTV08