@article{DAN_1962_145_5_a15,
     author = {L. N. Shevrin and V. M. Kopytov},
     title = {Semigroups with relatively complemented subsemigroups},
     journal = {Doklady Akademii Nauk},
     pages = {1012--1015},
     year = {1962},
     volume = {145},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1962_145_5_a15/}
}