%0 Journal Article %A V. E. Fedorov %T Weak solutions of linear equations of Sobolev type and semigroups of operators %J Izvestiya. Mathematics %D 2003 %P 797-813 %V 67 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/IM2_2003_67_4_a4/ %G en %F IM2_2003_67_4_a4