@article{IM2_1980_14_3_a1,
     author = {G. S. Makanin},
     title = {Recognition of the rank of equations in a~free semigroup},
     journal = {Izvestiya. Mathematics},
     pages = {499--545},
     year = {1980},
     volume = {14},
     number = {3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1980_14_3_a1/}
}