Localization and transport in pseudoternary ruthenates
  The temperature dependence of the electrical resistivity of two chemically substituted Ca-ruthenates is examined with the Efros-Shklovskii mechanism invoking Coulomb interactions between carriers. Additional mechanisms causing an energy dependence to the density of states at the Fermi surface may explain the unusually wide temperature and conductivity range obeyed by one system. 
G. Cao, V. Dobrosavljevic, S. McCall, J. E. Crow and R. P. Guertin