@article{DCG_1993__10_2_131258,
     author = {B. Sturmfels and G. M. Ziegler},
     title = {Extension {Spaces} of {Oriented} {Matroids.}},
     journal = {Discrete & computational geometry},
     pages = {23--46},
     publisher = {mathdoc},
     volume = {10},
     number = {2},
     year = {1993},
     zbl = {0783.52009},
     url = {http://geodesic.mathdoc.fr/item/DCG_1993__10_2_131258/}
}