en Aichholzer, Oswin; Krasser, Hannes (), „Abstract order type extension and new results on the rectilinear crossing number”, Computational Geometry, 36 (1): 2–15, doi:10.1016/j.comgeo.2005.07.005, MR2264046
doi.org
en Gropp, Harald (), „Configurations and their realization”, Discrete Mathematics, 174 (1–3): 137–151, doi:10.1016/S0012-365X(96)00327-5
en Aichholzer, Oswin; Krasser, Hannes (), „Abstract order type extension and new results on the rectilinear crossing number”, Computational Geometry, 36 (1): 2–15, doi:10.1016/j.comgeo.2005.07.005, MR2264046