@article{ADM_2014_17_1_a7, author = {A. Umar}, title = {Some combinatorial problems in the theory of partial transformation semigroups}, journal = {Algebra and discrete mathematics}, pages = {110--134}, publisher = {mathdoc}, volume = {17}, number = {1}, year = {2014}, language = {en}, url = {http://geodesic.mathdoc.fr/item/ADM_2014_17_1_a7/} }