Invariant classification of orthogonally separable Hamiltonian systems   in Euclidean space
  The problem of the invariant classification of the orthogonal coordinate webs defined in Euclidean space is solved within the framework of Felix Klein's Erlangen Program. The results are applied to the problem of integrability of the Calogero-Moser model. 
Joshua T. Horwood, Raymond G. McLenaghan, and Roman G. Smirnov