@article{IM2_2003_67_4_a4,
     author = {V. E. Fedorov},
     title = {Weak solutions of linear equations of {Sobolev} type and semigroups of operators},
     journal = {Izvestiya. Mathematics },
     pages = {797--813},
     publisher = {mathdoc},
     volume = {67},
     number = {4},
     year = {2003},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2003_67_4_a4/}
}