TY - JOUR AU - Walenty Ostasiewicz TI - Calculus of fuzzy numbers JO - Mathematica Applicanda PY - 1979 SP - 47 EP - 60 VL - 7 IS - 15 PB - mathdoc UR - http://geodesic.mathdoc.fr/articles/10.14708/ma.v7i15.1478/ DO - 10.14708/ma.v7i15.1478 LA - pl ID - 10_14708_ma_v7i15_1478 ER -