 On a sumset conjecture by Erdös. (with I. Goldbring, R. Jin, S.
Leth, M.Lupini, K. Mahlburg), Canadian Journal of Mathematics,
vol. 67 (2015), pp. 795809.
 The eightfold
path to
nonstandard analysis
(with
V. Benci and M. Forti), in
"Nonstandard Methods and Applications in
Mathematics" (N.J. Cutland, M. Di Nasso and
D.A. Ross, eds.), Lecture
Notes in Logic vol. 25, ASL, AK Peters, 2006,
pp. 344.
 Hausdorff
ultrafilters
(with M.
Forti), Proceedings
of the American Mathematical Society, vol. 134
(2006), pp. 18091818.

