@article{IVM_2000_5_a8,
     author = {V. P. Serebryakov},
     title = {On the deficiency index of second-order matrix differential operators},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {62--67},
     year = {2000},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_2000_5_a8/}
}