Generalized Self-similar Scalar-Tensor Theories
  We study through symmetry principles the form of the functions in the generalizated scalar-tensor theories under the self-similar hypothesis. The results obtained are absolutely general and valid for all the Bianchi models and the flat FRW one. We study the concrete example of the Kantowsky-Sach model finding some exact self-similar solutions. 
J. A. Belinch\'on
gr-qc