@article{MZM_1985_38_6_a10,
     author = {A. V. Knyazev},
     title = {Sharp a priori error estimates of the {Rayleigh--Ritz} method without assumptions of fixed sign or compactness},
     journal = {Matemati\v{c}eskie zametki},
     pages = {900--907},
     publisher = {mathdoc},
     volume = {38},
     number = {6},
     year = {1985},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1985_38_6_a10/}
}