TY  - RPRT
TI  - Modular group, operator ordering, and time in (2+1)-dimensional gravity.
AU  - S Carlip
PY  - 1993
DO  - 10.1103/physrevd.47.4520
UR  - https://pubmed.ncbi.nlm.nih.gov/10015451/
ID  - 10015451
ER  -