1. Bell Laboratories, “The traveling salesman problem: 1934–1978,” Bibliography No. 367 (Holmdel, NY, 1979).
2. C. Berge,Graphs and Hypergraphs (North-Holland, Amsterdam, 1973).
3. D. Bienstock, E.F. Brickell and C.L. Monma, “Properties ofk-connected networks,”SIAM Journal on Discrete Mathematics, to appear.
4. N. Christofides, “Worst-case analysis of a new heuristic for the traveling salesman problem,” Technical Report, GSIA, Carnegie-Mellon University (Pittsburgh, PA, 1976).
5. N. Christofides, “The traveling salesman problem,” in: N. Christofides et al., eds.,Combinatorial Optimization (Wiley, New York, 1979) pp. 131–150.