@article{DAN_1977_232_5_a5,
     author = {A. P. Kombarov},
     title = {Normal $\sigma$-products},
     journal = {Doklady Akademii Nauk},
     pages = {1004--1007},
     publisher = {mathdoc},
     volume = {232},
     number = {5},
     year = {1977},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1977_232_5_a5/}
}