@article{ZNSL_1972_28_a7,
     author = {Yu. A. Drozd},
     title = {Matrix problems and the cathegories of matrices},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {144--153},
     year = {1972},
     volume = {28},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1972_28_a7/}
}