@article{DAN_1972_207_4_a3,
     author = {M. Lomkovskaya},
     title = {Conditional grammars and intermediate classes of languages},
     journal = {Doklady Akademii Nauk},
     pages = {781--784},
     publisher = {mathdoc},
     volume = {207},
     number = {4},
     year = {1972},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1972_207_4_a3/}
}