%0 Journal Article %A V. N. Popov %A P. A. Sevastianov %T Collective excitations in the ferro- and antiferromagnetic states of the two-dimensional repulsive Hubbard model %J Zapiski Nauchnykh Seminarov POMI %D 1994 %P 229-259 %V 209 %U http://geodesic.mathdoc.fr/item/ZNSL_1994_209_a12/ %G ru %F ZNSL_1994_209_a12