1. F. Alizadeh, “Optimization Over Positive Semi-Definite Cone; Interior-Point Methods and Combinatorial Applications”. In “Advances in Optimization and Parallel Computing”, P.M. Pardalos, editor, North-Holland, 1992.
2. S. Arora and S. Safra, “Probabilistic checking of proofs: A new characterization of NP”. Proceedings of the 33rd IEEE Symp. on Foundations of Computer Science, pp. 2-13, 1992.
3. S. Arora, C. Lund, R. Motwani, M. Sudan and M. Szegedy, “Proof verification and hardness of approximation problems”. Proceedings of the 33rd IEEE Symp. on Foundations of Computer Science, pp. 14-23, 1992.
4. D.-Z. Du and F.K. Hwang, “An approach for proving lower bounds: solution of Gilbert-Pollak’s conjecture on the Steiner ratio”. Proceedings of 31th FOCS Conference, pp. 76-85, 1990.
5. D.-Z. Du, D.F. Hsu and K.-J Xu, “Bounds on guillotine ratio”. Congressus Numerantium 58, pp. 313–318, 1987.