The Bethe lattice spin glass at zero temperature P. M. Bleher (1991) Annales de l'I.H.P. Physique théorique
The condition of quasiperiodicity in imaginary time as a constraint at the functional integration and the time-dependent Z Z -correlator of the X X Heisenberg magnet. Malyshev, K. (2004) Zapiski Nauchnykh Seminarov POMI