@article{AL_1998_37_4_a5,
     author = {E. V. Sukhanov and A. M. Shur},
     title = {On a class of formal languages},
     journal = {Algebra i logika},
     pages = {478--492},
     publisher = {mathdoc},
     volume = {37},
     number = {4},
     year = {1998},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1998_37_4_a5/}
}