1. G. ’t Hooft, M.J.G. Veltman, Ann. Henri Poincaré Phys. Theor. A 20, 69 (1974)
2. M.H. Goroff, A. Sagnotti, Phys. Lett. B 160, 81 (1985)
3. A.E.M. van de Ven, Nucl. Phys. B 378, 309 (1992)
4. M. Niedermaier, M. Reuter, Living Rev. Relativ. 7, 9 (2006). http://www.livingreviews.org/lrr-2006-5
5. M. Reuter, F. Saueressig, in Geometric and Topological Methods for Quantum Field Theory, ed. by H. Ocampo, S. Paycha, A. Vargas (Cambridge University Press, Cambridge, 2010). arXiv:0708.1317