1. The main idea discussed in this paper was originally developed by R. Contino, A. Pomarol and R. Rattazzi in unpublished work, see R. Rattazzi, The naturally light dilaton, talk at Planck 2010, indico/contribId=163&confId=75810 , CERN, Geneva Switzerland (2010).
2. See also talk by A. Pomarol, Elementary or composite: the particle physics dilemma, talk at Xmas10, http://www.ift.uam-csic.es/workshops/Xmas10/doc/pomarol.pdf , Madrid Spain December 15–17 2010.
3. A. Salam and J. Strathdee, Nonlinear realizations. 2. Conformal symmetry, Phys. Rev. 184 (1969) 1760 [ INSPIRE ].
4. C. Isham, A. Salam and J. Strathdee, Spontaneous breakdown of conformal symmetry, Phys. Lett. B 31 (1970) 300 [ INSPIRE ].
5. C. Isham, A. Salam and J. Strathdee, Nonlinear realizations of space-time symmetries. Scalar and tensor gravity, Annals Phys. 62 (1971) 98 [ INSPIRE ].