1. Tel-Aviv Univ., Tel-Aviv, Israel and AT&T Bell Labs, Murray Hill, NJ
2. Technion, Haifa, Israel
3. Hebrew Univ., Jerusalem, Israel and IBM Almaden Research Center, San Jose, CA
4. Tel-Aviv Univ., Tel-Aviv, Israel and Univ. of California, Los Angeles
5. AT&T Bell Labs, Murray Hill, NJ
6. IBM Almaden Research Center, San Jose, CA and Stanford Univ., Stanford, CA