1. Circuits and trees in oriented linear graphs;van Aardenne-Ehrenfest;Simon Stevin: Wis- en Natuurkundig Tijdschrift,1951
2. Greedy algorithm and symmetric matroids;Bouchet;Math. Program.,1987
3. Isotropic systems;Bouchet;European J. Combin.,1987
4. Graphic presentations of isotropic systems;Bouchet;J. Combin. Theory Ser. B,1988
5. Representability of Δ-matroids;Bouchet,1988