Some FRW models with variable G and cosmological constant
  We consider several model with metric type FRW, with k=0 and with generic equation of state. We take into account too, the conservation principle for the energy-momentum tensor. We find trivially, a set of solutions through dimensional analysis. We emphasite that the solution for G depend on the equation of state and for the cosmological constant no. 
J. A. Belinchon