Jürgen Bokowski Tomaz Pisanski Oriented matroids and complete-graph embeddings on surfaces. 1-19 2007 114 J. Comb. Theory, Ser. A 1 http://dx.doi.org/10.1016/j.jcta.2006.06.012 db/journals/jct/jcta114.html#BokowskiP07