Voir la notice de l'article provenant de la source Math-Net.Ru
@article{MZM_1968_3_6_a4, author = {E. S. Lyapin}, title = {Defining relations of semigroups of all directed transformations of an~ordered finite set}, journal = {Matemati\v{c}eskie zametki}, pages = {657--662}, publisher = {mathdoc}, volume = {3}, number = {6}, year = {1968}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1968_3_6_a4/} }
E. S. Lyapin. Defining relations of semigroups of all directed transformations of an~ordered finite set. Matematičeskie zametki, Tome 3 (1968) no. 6, pp. 657-662. http://geodesic.mathdoc.fr/item/MZM_1968_3_6_a4/