Generalized Fluctuation Theory based on the reparametrization invariance   of the microcanonical ensemble
  The main interest of the present work is the generalization of the Boltzmann-Gibbs distributions and the fluctuation theory based on the consideration of the reparametrization invariance of the microcanonical ensemble. This approach allows a novel interpretation of some anomalous phenomena observed in the non extensive systems like the existence of the negative specific heats as well as possibilities the enhancing of some Monte Carlo methods based on the Statistical Mechanics. 
L. Velazquez