@article{IVM_1982_6_a4,
     author = {E. S. Lyapin},
     title = {Abstract characterization of a~class of partial groupoids of transformations},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {30--36},
     publisher = {mathdoc},
     number = {6},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1982_6_a4/}
}