@article{MZ_1993__212_4_174469,
     author = {G\"unter M. Ziegler},
     title = {On the difference between real and complex arrangements.},
     journal = {Mathematische Zeitschrift},
     pages = {1--12},
     year = {1993},
     volume = {212},
     number = {4},
     zbl = {0789.57018},
     url = {http://geodesic.mathdoc.fr/item/MZ_1993__212_4_174469/}
}