@article{AL_1966_5_3_a3,
     author = {V. D. Luchkin},
     title = {Ranks of configurations of context-free languages},
     journal = {Algebra i logika},
     pages = {59--70},
     publisher = {mathdoc},
     volume = {5},
     number = {3},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_1966_5_3_a3/}
}