Michael B. Mensky
P.N.Lebedev Physical Institute, Moscow
Problem of Time in Quantum Cosmology
M. B. Mensky, The self-measurement of the Universe and the concept of time in quantum cosmology, Class. and Quantum Gravity 7, 2317-2329 (1990)
See also: Michael B. Mensky, Continuous Quantum Measurements and Path Integrals. IOP Publishing, Bristol and Philadelphia, 1993, Chapter 8.