1. Balas, E. and M.W. Padberg: Lectures on Set Packing and Set Partitioning, this volume.
2. to appear in Operations Research;R Balas,1974
3. Berge, C.: Graphes et Hypergraphes, Dunod, Paris 1970.
4. Berge, C.: Introduction à la Théorie des Hypergraphes, Lectures notes, Université de Montréal, Summer 1971.
5. Berge, C.: Balanced Matrices, Mathematical Programming, Vol. 2 (1972), pp. 19–31.