@article{MZM_2008_84_2_a10,
     author = {K. A. Shramov},
     title = {Birational {Rigidity} and $\mathbb Q${-Factoriality} of a {Singular} {Double} {Cover} of a {Quadric}  {Branched} over a {Divisor} of {Degree~4}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {300--311},
     publisher = {mathdoc},
     volume = {84},
     number = {2},
     year = {2008},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2008_84_2_a10/}
}