user- (2003)cite arxiv:hep-th/0306013 Comment: 20 pages, no figures, LaTex. This version has exactly the same technical content as version 1, but the observation r...cite arxiv:hep-th/0306013 Comment: 20 pages, no figures, LaTex. This version has exactly the same technical content as version 1, but the observation reported in Section VII is discussed more pedagogically.
- (2007)cite arxiv:0711.3222 Comment: 13 pages, no figures. To appear in the proceedings of the workshop "From Quantum to Emergent Gravity: Theory and Phe...cite arxiv:0711.3222 Comment: 13 pages, no figures. To appear in the proceedings of the workshop "From Quantum to Emergent Gravity: Theory and Phenomenology", Trieste, Italy, June 11-15 2007.
- (1994)cite arxiv:hep-th/9405107 Comment: 12 pages. Revision: minor typos corrected .
