@article{ELMA_1973__28_141110,
     author = {H. Ratschek},
     title = {Intervallarithmetik - mit {Zirkel} und {Lineal.}},
     journal = {Elemente der Mathematik},
     pages = {93--96},
     year = {1973},
     volume = {28},
     zbl = {0277.65022},
     url = {http://geodesic.mathdoc.fr/item/ELMA_1973__28_141110/}
}