@article{IM2_2015_79_2_a0,
     author = {A. G. Baskakov and A. Yu. Duplishcheva},
     title = {Difference operators and operator-valued matrices of the second order},
     journal = {Izvestiya. Mathematics },
     pages = {217--232},
     publisher = {mathdoc},
     volume = {79},
     number = {2},
     year = {2015},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_2015_79_2_a0/}
}