ac Susceptibility in Granular Superconductors: Theory and Experiment
  A phenomenological theory to describe the electromagnetic properties of granular superconductors, based on known bulk superconductors expressions and conventional Josephson's junctions tunneling currents, is presented and succesfully used to fit distinct experimental results for the magnetic susceptibility as a function of the temperature and the applied magnetic field of rather different samples. 
A. Kunold, M. Hernandez, A. Myszkowki, J.L. Cardoso, P. Pereyra