@article{MZM_2001_69_2_a0,
     author = {A. I. Astrovskii},
     title = {Generalized {Gram} {Matrix} and {Its} {Application} to the {Observability} {Problem} for {Linear} {Nonsteady} {Systems}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {163--170},
     publisher = {mathdoc},
     volume = {69},
     number = {2},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2001_69_2_a0/}
}