@article{SM_1988_61_2_a1,
     author = {A. S. Markus and V. I. Matsaev},
     title = {On the basis property for a~certain part of the eigenvectors and associated vectors of a~selfadjoint operator pencil},
     journal = {Sbornik. Mathematics},
     pages = {289--307},
     publisher = {mathdoc},
     volume = {61},
     number = {2},
     year = {1988},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1988_61_2_a1/}
}