@article{IVM_1971_11_a6,
     author = {V. S. Garvatskii},
     title = {Pencils and connectivity relations on semigroups},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {45--56},
     publisher = {mathdoc},
     number = {11},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1971_11_a6/}
}