@article{DAN_1962_147_2_a16,
     author = {Yu. I. Yanov},
     title = {On identical transformations of regular expressions},
     journal = {Doklady Akademii Nauk},
     pages = {327--330},
     publisher = {mathdoc},
     volume = {147},
     number = {2},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1962_147_2_a16/}
}