1. On the shortest spanning subgraph of a graph and the traveling salesman problem;Kruskal,1956
2. Note on independence functions;Rado,1957
3. Optimal assignments in an ordered set: An application of matroid theory;Gale;Journal of Combinatorial Theory,1968
4. Greedoids;Korte,1991
5. Greedy algorithm and symmetric matroids;Bouchet;Mathematical Programming,1987