@article{TMF_1977_33_2_a6,
     author = {N. N. Bogolyubov (Jr.) and D. Ya. Petrina},
     title = {On a class of model systems that admit a~lowering of powers in the {Hamiltonian} in the thermodynamic limit. {I}},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {231--245},
     publisher = {mathdoc},
     volume = {33},
     number = {2},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1977_33_2_a6/}
}