TY  - RPRT
TI  - Finite diffeomorphism-invariant observables in quantum gravity.
AU  - L Smolin
PY  - 1994
DO  - 10.1103/physrevd.49.4028
UR  - https://pubmed.ncbi.nlm.nih.gov/10017407/
ID  - 10017407
ER  -