1. Tres observaciónes sobre el algebra lineal;Birkhoff;Univ. Nac. Tucuman, Rev. Ser. A,1946
2. A proof of Fulkerson's characterization of permutation matrices;Cruse;Linear Algebra Appl.,1975
3. Optimum branchings;Edmonds;J. Res. Natl. Bur. Stand.,1967
4. Submodular functions, matroids, and certain polyhedra;Edmonds,1970
5. Jack Edmonds, Matroid intersection, to be published.