TY - JOUR AU - Geffert, Viliam TI - Normal forms for phrase-structure grammars JO - RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications PY - 1991 SP - 473 EP - 496 VL - 25 IS - 5 PB - EDP-Sciences UR - http://archive.numdam.org/item/ITA_1991__25_5_473_0/ LA - en ID - ITA_1991__25_5_473_0 ER -