Intrinsic time in Friedmann-Robertson-Walker universe
  A global intrinsic time in Friedmann - Robertson - Walker models is proportional to a scaling factor of the spatial metric. The aim of the paper is to study an applicability of the intrinsic global time chosen to nearest non-symmetric cases by taking into account linear metric perturbations. Scalar linear perturbations add some corrections to the effective energy density in the Hubble law. The metric vector and tensor perturbations in linear approximation do not influence the intrinsic time. 
Alexander Pavlov
gr-qc