@article{ZNSL_1980_93_a2,
     author = {A. M. Istamov},
     title = {The asymptotical behavior of integer matrices of second order in the hyperbolic domain and belonging to the residue class},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {25--29},
     publisher = {mathdoc},
     volume = {93},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1980_93_a2/}
}