1. P. Erdös, A. L. Rubin and H. Taylor, Choosability in graphs, in: Proc. West Coast Conf. on Combinatorics, Graph Theory and Computing (Humboldt State University, 1979) 125–157.
2. On the complexity of timetable and multicommodity flow problems;Even;SIAM J. Comput.,1976
3. Scheduling unit-time tasks with integer release times and deadlines;Frederickson;Inf. Process. Lett.,1983
4. The NP-completeness column: An ongoing guide;Johnson;J. Algorithms,1983
5. Reducibility among combinatorial problems;Karp,1972