1. E. Balas (1980), ‘Cutting planes from conditional bounds: A new approach to set convering’,Mathematical Programming, Vol. 12, pp. 19–36.
2. E. Ballas and A. Ho (1980), ‘Set covering algorithms using cutting planes, heuristics, and subgradient optimization’,Mathematical Programming, Vol. 12, pp. 37–60.
3. O. Bjorke and B. Haugrud (1967), ‘Mathematical methods in planning of machining operations’, Presented at the CIRP Meeting, Ann Arbor, Michigan.
4. J. A. Buzacott (1983), ‘The fundamental principles of flexibility in manufacturing systems’, Proceedings of the 1st Int. Conf. on Flexible Manufacturing Systems, Brighton, UK, pp. 13–22.
5. T. C. Chang and A. Wysk (1985),An Introduction to Automated Process Planning Systems, Prentice-Hall, Englewood Cliffs, NJ.