1. D.N. Page and C.D. Geilker, Indirect evidence for quantum gravity, Phys. Rev. Lett. 47 (1981) 979 [ INSPIRE ].
2. G. ’t Hooft and M. Veltman, One loop divergencies in the theory of gravitation, Annales Poincare Phys. Theor. A 20 (1974) 69.
3. S. Deser and P. van Nieuwenhuizen, One loop divergences of quantized Einstein-Maxwell fields, Phys. Rev. D 10 (1974) 401 [ INSPIRE ].
4. S. Deser and P. van Nieuwenhuizen, Nonrenormalizability of the quantized Dirac-Einstein system, Phys. Rev. D 10 (1974) 411 [ INSPIRE ].
5. S. Deser and P. van Nieuwenhuizen, Nonrenormalizability of the quantized Einstein-Maxwell system, Phys. Rev. Lett. 32 (1974) 245 [ INSPIRE ].