1. S. Beraha, “Infinite Non-Trivial Families of Maps and Chromials” thesis, Johns Hopkins University.
2. Is the four-color conjecture almost false?;Beraha;J. Combinatorial Theory Ser. B,1979
3. Limits of zeros of recursively defined families of polynomials, Studies in Foundations and Combinatorics;Beraha;Advances in Math., Supplementary Studies,1978
4. Chromatic polynomials;Birkhoff;Trans. Amer. Math. Soc.,1946