TY - JOUR AU - Păun, Gheorghe TI - Two infinite hierarchies of languages defined by branching grammars JO - Kybernetika PY - 1978 SP - EP - 407 VL - 14 IS - 6 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/KYB_1978__14_6_a1/ LA - en ID - KYB_1978__14_6_a1 ER -