@article{RM_1962_17_3_a5,
     author = {K. A. Zaretskii},
     title = {Regular elements of the semigroup of binary relations},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {17},
     number = {3},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1962_17_3_a5/}
}