@article{10_14708_ma_v7i15_1478,
     author = {Walenty Ostasiewicz},
     title = {Calculus of fuzzy numbers},
     journal = {Mathematica Applicanda},
     pages = { 47--60},
     publisher = {mathdoc},
     volume = {7},
     number = {15},
     year = {1979},
     doi = {10.14708/ma.v7i15.1478},
     language = {pl},
     url = {http://geodesic.mathdoc.fr/articles/10.14708/ma.v7i15.1478/}
}