  It was discussed the possibility of determination of 2D XY ordering
temperature (Berezinskii-Kosterlitz-Thouless temperature) in striped Cu-O
planes for quasi-two dimensional HTS with the semiconducting behavior of
out-of-plane resistivity in normal state. From the results of the resistivity
measurements for samples of underdoped Bi-2212 the values of 2D XY ordering
temperature were found out. Its are compared with the results of the
measurements of frequency dependent conductivity. It is shown that these both
results give the value of 2D XY ordering temperature ~62 K for samples with
Tc=74 K and verify the importance of taken into account two dimensional
superconducting fluctuations at T>Tc.
