@article{TMF_1975_23_3_a6,
     author = {V. I. Savrin and N. E. Tyurin},
     title = {Analytic properties of the $U$ matrix},
     journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
     pages = {348--354},
     publisher = {mathdoc},
     volume = {23},
     number = {3},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_1975_23_3_a6/}
}