1. On the set covering problem;Balas;Oper. Res.,1972
2. On the set covering problem: II;Balas;Oper. Res.,1975
3. Set partitioning: A survey;Balas,1975
4. The use of the TNP-rule to solve various degeneracy problems;Gal,1990
5. An extension of a theorem of Dantzig's;Heller,1956