@article{DAN_1972_204_1_a10,
     author = {S. M. Ponomarev},
     title = {On convergence of semigroups},
     journal = {Doklady Akademii Nauk},
     pages = {42--44},
     publisher = {mathdoc},
     volume = {204},
     number = {1},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_204_1_a10/}
}