1. AUSIELLO, G., D'ATRI, A., AND PROTASSI,M. (1977). On the Structure of Combinatorial Problems and Structure Preserving Reductions, Proc. 4th Intl. Coll. on Automata, Languages and Programming, 45–57.
2. AUSIELLO, G., D'ATRI, A., and PROTASSI, M. (1980). Structure Preserving Reductions among Convex Optimization Problems, J. Comp. Sys. Sc. 21, 136–153.
3. AUSIELLO, G., MARCHETTI-SPACCAMELA, A., and PROTASSI, M. (1980). Towards a Unified Approach for the Classification of NP-Complete Optimization Problems", 12, 83–96.
4. CHERNOFF, H. (1952). A Measure of Asymptotic Efficiency for Tests of a Hypothesis Based on the Sum of Observations, Ann. of Math. Stat. 23, 493–507.
5. ERDOES, P., AND SPENCER, J. (1974). Probabilistic Methods in Combinatorics, Academic Press.