@article{MZM_1978_24_1_a6,
     author = {V. A. Belyaev},
     title = {Grouped power series},
     journal = {Matemati\v{c}eskie zametki},
     pages = {53--62},
     publisher = {mathdoc},
     volume = {24},
     number = {1},
     year = {1978},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1978_24_1_a6/}
}