1. 2 + 1 dimensional gravity as an exactly soluble system
2. Exactly soluble diffeomorphism invariant theories;Horowitz,1989
3. Exact quantum scattering in 2+1 dimensional gravity;Carlip,1989
4. Observables in 2+1 dimensional gravity;Martin,1989
5. 2+1 quantum gravity as a toy model for the 3+1 theory;Ashtekar,1989