@article{DAN_1968_179_3_a12,
     author = {B. M. Rudyk},
     title = {Extensions of modules},
     journal = {Doklady Akademii Nauk},
     pages = {545--547},
     publisher = {mathdoc},
     volume = {179},
     number = {3},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_179_3_a12/}
}