@article{IM2_1978_12_2_a0,
     author = {S. I. Adian and G. U. Oganesyan},
     title = {On the word and divisibility problems in semigroups with a~single defining relation},
     journal = {Izvestiya. Mathematics},
     pages = {207--212},
     year = {1978},
     volume = {12},
     number = {2},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1978_12_2_a0/}
}