1. L. Adleman and K. Manders. Reducibility, randomness and intractability, In Proceedings of the 9th ACM Sympos. Theory of Computing 151–163.
2. E. Allender, L. Hemachandra, M. Ogiwara, and O. Watanabe. Relating equivalence and reducibility to sparse sets. Proceeding 6th Structure in Complexity Theory Conference, 1991.
3. [AHH+92] V. Arvind, Y. Han, L. Hemachandra, J. Köbler, A. Lozano, M. Mundhenk, M. Ogiwara, U. Schöning, R. Silvestri, and T. Thierauf. Reductions to sets of low information content. In Proceedings of the 19th International Colloquium on Automata, Languages, and Programming. To appear.
4. V. Arvind, J. Köbler, and M. Mundhenk. Bounded truth-table and conjunctive reductions to sparse and tally sets. Ulmer Informatik Berichte 92–01, 1992.
5. J. Balcázar, R. Book, and U. Schöning. Sparse sets, lowness and highness. SIAM J. Comput., 15:739–745, 1986.