  We measured isofield magnetization curves as a function of temperature in two
single crystal of deoxygenated YBaCuO with T_c = 52 and 41.5 K. Isofield MvsT
were obtained for fields running from 0.05 to 4 kOe. The reversible region of
the magnetization curves was analyzed in terms of a scaling proposed by Prange,
but searching for the best exponent $\upsilon$. The scaling analysis carried
out for each data sample set with $\upsilon$=0.669, which corresponds to the
3D-xy exponent, did not produced a collapsing of curves when applied to MvsT
curves data obtained for the lowest fields. The resulting analysis for the Y123
crystal with T_c = 41.5 K, shows that lower field curves collapse over the
entire reversible region following the Prange's scaling with $\upsilon$=1,
suggesting a two-dimensional behavior. It is shown that the same data obeying
the Prange's scaling with $\upsilon$=1 for crystal with T_c = 41.5 K, as well
low field data for crystal with $T_c$ = 52 K, obey the known two-dimensional
scaling law obtained in the lowest-Landau-level approximation.
