1. H. L. Abbott and G. Exoo, “On set systems not containing Delta systems”, Graphs and Combinatorics, 8, 1992, 1–9.
2. H. L. Abbott and B. Gardner, “On a combinatorial theorem of Erdös and Rado”, in: W. T. Tutte, ed., Recent progress in Combinatorics, Academic Press, New York, 1969, 211–215.
3. H. L. Abbott and D. Hanson, “On finite A-systems”, Discrete Math., 8, 1974, 1–12.
4. H. L. Abbott and D. Hanson, “On finite A-systems, II”, Discrete Math., 17, 1977, 121–126.
5. H. L. Abbott, D. Hanson, and N. Sauer, “Intersection theorems for systems of sets”, Journal of Combinatorial Theory, Series A, 12, 1972, 381–389.