1. Abdel-Wahab, H. M.: Scheduling with applications to register allocation and deadlock problems. Ph. D. Thesis, University of Waterloo, 1976.
2. Abdel-Wahab, H. M., Kameda, T.: Scheduling to minimize the maximum cumulative cost subject to series-parallel precedence constraints. Opns. Res.26, 141–159 (1977).
3. Aho, A. V., Hopcroft, J. E., Ullman, J. D.: The design and analysis of computer algorithms. Reading, Mass: Addison-Wesley 1974.
4. Cook, S. A.: The complexity of theorem-proving procedures. Proc. Third Annual ACM Symp. Theory of Computing, Shaker Heights, Ohio, 1970, 151–158.
5. Karp, R. M.: Reducibility among combinatorial problems, in: Complexity of Computer Computations (Miller, R. E., Thatcher, J. W., eds.), pp. 85–103. New York: Plenum Press 1973.