@article{KUTGS_1997_23_a16,
     author = {A. P. Shirokov},
     title = {The space $H_4$ and quaternion algebra},
     journal = {Trudy Geometricheskogo Seminara},
     pages = {187--198},
     publisher = {mathdoc},
     volume = {23},
     year = {1997},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/KUTGS_1997_23_a16/}
}