@article{MZM_1990_47_3_a18,
     author = {Chan Tkhu Kha},
     title = {A~nonselfadjoint operator pencil},
     journal = {Matemati\v{c}eskie zametki},
     pages = {133--135},
     publisher = {mathdoc},
     volume = {47},
     number = {3},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_47_3_a18/}
}