@article{KYB_1973_9_3_a0,
     author = {Kr\'al, Jaroslav},
     title = {A note on grammars with regular restrictions},
     journal = {Kybernetika},
     pages = {159--161},
     year = {1973},
     volume = {9},
     number = {3},
     mrnumber = {0327092},
     zbl = {0277.68044},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/KYB_1973_9_3_a0/}
}