TY - JOUR AU - Gruska, Jozef TI - Two Operations with Formal Languages and their Influence upon Structural Unambiguity JO - Mathematica slovaca PY - 1966 SP - 58 EP - 65 VL - 16 IS - 1 UR - http://geodesic.mathdoc.fr/item/MASLO_1966_16_1_a8/ LA - en ID - MASLO_1966_16_1_a8 ER -