@article{ZNSL_1995_224_a23,
     author = {V. S. Yarunin},
     title = {The two-branch spectrum of excitations of the {Bose-condensate}},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {310--317},
     year = {1995},
     volume = {224},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1995_224_a23/}
}