Felipe Cucker, Dima Grigoriev. There are No Sparse NP::w::-Hard Sets. SIAM Journal on Computing, 31(1):193-198, 2001. [doi]
@article{CuckerG01:0, title = {There are No Sparse NP::w::-Hard Sets}, author = {Felipe Cucker and Dima Grigoriev}, year = {2001}, url = {http://epubs.siam.org/sam-bin/dbq/article/37934}, researchr = {https://researchr.org/publication/CuckerG01%3A0}, cites = {0}, citedby = {0}, journal = {SIAM Journal on Computing}, volume = {31}, number = {1}, pages = {193-198}, }