@article{PDM_2009_10_a37,
     author = {O. I. Egorushkin and K. V. Safonov},
     title = {Analitic approach to context-free languages in the {Greibach} normal form},
     journal = {Prikladna\^a diskretna\^a matematika},
     pages = {73--74},
     year = {2009},
     number = {10},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/PDM_2009_10_a37/}
}