1. N. Alon andF. R. K. Chung, Explicit constructions of linear-sized tolerant networks,to appear.
2. J. Beck, On size Ramsey number of paths, trees, and circuits. I,J. Graph Theory,7 (1983), 115–129.
3. L. Lovász,Combinatorial problems and exercises, North-Holland, 1979.
4. A. Lubotzky, R. Phillips andP. Sarnak, Ramanujan graphs,to appear.
5. L. Pósa, Hamiltonian circuits in random graphs,Discrete Math.,14 (1976), 359–364.