%0 Journal Article %A S. A. Fedotov %T Phase transition in the model two-level system %J Zapiski Nauchnykh Seminarov POMI %D 1981 %P 184-195 %V 101 %I mathdoc %U http://geodesic.mathdoc.fr/item/ZNSL_1981_101_a14/ %G ru %F ZNSL_1981_101_a14