1. R. E. Bixby,l-matrices and a characterization of binary matroids,Discrete Math. 8 (1974), 139–145.
2. N. Robertson andK. Chakravarti, Covering three edges with a bond in a non-separable graph, in:Combinatorics 79, part I (eds. M. Deza and I. G. Rosenberg)Annals of Discrete Math. (North Holland, Amsterdam),8 (1980), 247.
3. P. D. Seymour, A note on the production of matroid minors,J. Combinatorial Theory, Ser. B 22 (1977), 289–295.
4. P. D. Seymour, Decomposition of regular matroids,J. Combinatorial Theory, Ser. B 28 (1980), 305–359.
5. W. T. Tutte, A homotopy theorem for matroids, I, II,Trans. Amer. Math. Soc. 88 (1958), 144–174.