Cosmological Models with Variable Constants.Their Solution Through   Similarity Methods
  In this work we compile a few differential equations (ODEs) that arise from the relativistic equations in cosmological models that consider the ``constants'' as scalars functions dependent on time and they are described as perfect as well as viscous fluids. The general idea of the paper is to show how to solve the equations of the models through dimensional techniques (self-similarity). The results are compared with those obtained by other authors and new solutions are introduced. 
Jos\'e Antonio Belinch\'on and P. D\'avila