@article{IVM_1969_5_a10,
     author = {B. M. Shain},
     title = {Restrictive bisemigroups of quasi-single-valued binary {relations.~I}},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {73--84},
     publisher = {mathdoc},
     number = {5},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1969_5_a10/}
}