Functional self-similarity and renormalization group symmetry in   mathematical physics
  The result from developing and applying the notions of functional self-similarity and the Bogoliubov renormalization group to boundary-value problems in mathematical physics during the last decade are reviewed. The main achievement is the regular algorithm for finding renormalization group-type symmetries using the contemporary theory of Lie groups of transformations. 
Vladimir F. Kovalev and Dmitrij V. Shirkov