David W. Juedes, Jack H. Lutz. The Complexity and Distribution of Hard Problems. SIAM Journal on Computing, 24(2):279-295, 1995.
@article{JuedesL95:0, title = {The Complexity and Distribution of Hard Problems}, author = {David W. Juedes and Jack H. Lutz}, year = {1995}, researchr = {https://researchr.org/publication/JuedesL95%3A0}, cites = {0}, citedby = {0}, journal = {SIAM Journal on Computing}, volume = {24}, number = {2}, pages = {279-295}, }