Venkatesan Guruswami Christopher Umans Salil P. Vadhan Unbalanced Expanders and Randomness Extractors from Parvaresh-Vardy Codes. 96-108 2007 conf/coco/2007 IEEE Conference on Computational Complexity http://doi.ieeecomputersociety.org/10.1109/CCC.2007.38 db/conf/coco/coco2007.html#GuruswamiUV07