@article{ZNSL_2018_470_a6,
     author = {V. I. Kopeiko},
     title = {Unitary symbols and factorization hyperbolic matrices},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {111--119},
     publisher = {mathdoc},
     volume = {470},
     year = {2018},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_2018_470_a6/}
}