@article{TMF_1977_31_2_a8,
     author = {V. G. Bar'yakhtar and D. A. Yablonskii},
     title = {Symmetry of a~magnet and structure of spin-wave {Hamiltonian}},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {233--238},
     year = {1977},
     volume = {31},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1977_31_2_a8/}
}