%0 Journal Article
%A Gruska, Jozef
%T On a classification of context-free languages
%J Kybernetika
%D 1967
%P 22-29
%V 3
%N 1
%U http://geodesic.mathdoc.fr/item/KYB_1967_3_1_a1/
%G en
%F KYB_1967_3_1_a1