@article{ZNSL_1981_101_a14,
     author = {S. A. Fedotov},
     title = {Phase transition in the model two-level system},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {184--195},
     publisher = {mathdoc},
     volume = {101},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1981_101_a14/}
}