  We review results of articles hep-th/0607056, hep-th/0610163 and 0704.1405
[hep-th]. Here we focus on establish the connection between the entropy
functional formalism of Sen and the standard Euclidean formalism taken at zero
temperature. We find that Sen's entropy function $f$ (on-shell) matches the
zero temperature limit of the Euclidean action. Moreover, Sen's near horizon
angular and electric fields agree with the chemical potentials that are defined
from the zero-temperature limit of the Euclidean formalism. Connection with the
Dual CFT thermodynamics is briefly discussed.
