@article{UZKU_2005_147_1_a16,
     author = {V. E. Fomin},
     title = {On principal directions of hyperquadric in {Hilbert} space},
     journal = {U\v{c}\"enye zapiski Kazanskogo universiteta. Seri\^a Fiziko-matemati\v{c}eskie nauki},
     pages = {173--180},
     publisher = {mathdoc},
     volume = {147},
     number = {1},
     year = {2005},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/UZKU_2005_147_1_a16/}
}