@article{AM2_1983__26_136985,
     author = {Arthur G. Werschulz},
     title = {Measuring uncertainty without a norm.},
     journal = {Aequationes mathematicae},
     pages = {74--82},
     publisher = {mathdoc},
     volume = {26},
     year = {1983},
     zbl = {0547.41029},
     url = {http://geodesic.mathdoc.fr/item/AM2_1983__26_136985/}
}