%0 Journal Article %A Păun, Gheorghe %T Two infinite hierarchies of languages defined by branching grammars %J Kybernetika %D 1978 %P -407 %V 14 %N 6 %I mathdoc %U http://geodesic.mathdoc.fr/item/KYB_1978__14_6_a1/ %G en %F KYB_1978__14_6_a1