1. Covering three edges with a bond in a non-separable graph, Combinatorics 79;Chakravarti;Annals of Discrete Math,1980
2. On matroid connectivity;Cunningham;J. Combin. Theory, Ser. B,1981
3. The subgraph homeomorphism problem;La Paugh,1978
4. L. Lovász, unpublished.
5. Lecture at Dallas A.M.S. meeting;Robertson,1974