1. Edge-disjoint branchings;Edmonds,1973
2. D. R. Fulkerson, Packing rooted directed cuts in a weighted directed graph, Technical report No. 157, Dept. of Operations Research, Cornell University.
3. Integral boundary points of convex polyhedra;Hoffman;Ann. of Math. Studies,1956
4. Minimax theorems for hypergraphs;Lovász,1974