1. R. Percacci, An Introduction to Covariant Quantum Gravity and Asymptotic Safety. 100 Years of General Relativity, vol. 3 (World Scientific, 2017). https://doi.org/10.1142/10369
2. M. Reuter, F. Saueressig, Quantum Gravity and the Functional Renormalization Group (Cambridge University Press, Cambridge, UK, 2019)
3. A. Eichhorn, An asymptotically safe guide to quantum gravity and matter. Front. Astron. Space Sci. 5, 47 (2019) [1810.07615]
4. S. Weinberg, Ultraviolet divergences in quantum theories of gravitation, in ed. by S.W. Hawking, W. Israel General Relativity: An Einstein Centenary Survey, vol. 790 (Cambridge University Press, Cambridge, UK, 1979)
5. M. Reuter, Nonperturbative evolution equation for quantum gravity. Phys. Rev. D57, 971 (1998) [hep-th/9605030]