@article{MZM_1988_44_6_a11,
     author = {V. P. Serebryakov},
     title = {Index of defect of a symmetric second-order differential operator on the space of vector-functions},
     journal = {Matemati\v{c}eskie zametki},
     pages = {833--842},
     publisher = {mathdoc},
     volume = {44},
     number = {6},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1988_44_6_a11/}
}