@article{SM_1981_39_2_a4,
     author = {V. F. Gaposhkin},
     title = {The local ergodic theorem for groups of unitary operators and second order stationary processes},
     journal = {Sbornik. Mathematics},
     pages = {227--242},
     publisher = {mathdoc},
     volume = {39},
     number = {2},
     year = {1981},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1981_39_2_a4/}
}