  In this paper, I revisit the constraints obtained by several authors
(Reichart et al. 1999; Eke et al. 1998; Henry 2000) on the estimated values of
Omegam, n and sigma_8 in the light of recent theoretical developments: 1) new
theoretical mass functions (Sheth & Tormen 1999, Sheth, Mo & Tormen 2001, Del
Popolo 2002b); 2) a more accurate mass-temperature relation, also determined
for arbitrary Omega_m and Omega_Lambda (Del Popolo 2002a).
