1. There are infinitely many Carmichael numbers;Alford;Ann. of Math.,1994
2. Zero-sum sets of prescribed size;Alon;Combinatorics,1993
3. Introduction to Commutative Algebra;Atiyah,1969
4. A problem on semi-groups;Burgess;Studia Sci. Math. Hungar.,1969
5. Zero-sum problems—a survey;Caro;Discrete Math.,1996