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@article{IVM_1974_9_a3, author = {V. S. Garvatskii}, title = {A~characterization of projection subsets in semigroups of transformations}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {27--40}, publisher = {mathdoc}, number = {9}, year = {1974}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1974_9_a3/} }
V. S. Garvatskii. A~characterization of projection subsets in semigroups of transformations. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 9 (1974), pp. 27-40. http://geodesic.mathdoc.fr/item/IVM_1974_9_a3/