1. S. Perlmutter et al., Nature 391 (1998) 51; Ap. J 517 (1999) 565; A. Riess et al., Astron. J 117 (1998) 207; B. Schmidt et al., Ap. J 507 (1998) 46; P. Garnavich et al., Ap. J 509 (1998) 74.
2. See the review, N.A. Bahcall, J.P. Ostriker, S. Perlmutter, J.P. Steinhardt, Science 284 (1999) 1481, astro-ph/9906463, and references therein.
3. See the review, V. Sahni, A. Starobinski, to appear in Int. J. Mod. Phys. D, astro-ph/9904398, and references therein.
4. R.A. Battye, M. Bucher, D. Spergel, astro-ph/9908047.
5. L. Parker, A. Raval, gr-qc/9908031; astro-ph/9908069.