1. Characterization of rational periodic sequences
2. Abu-Saris, R.M., 2005, A self-invertibility condition for global periodicity of difference equations. Preprint University of Sharjah, to appear in Appl. Math. Lett.
3. On global periodicity of difference equations
4. Characterization of Rational Periodic Sequences II
5. Balibrea, F. and Linero, A., Some new results and open problems on periodicity of difference equations. To appear in the Proccedings of ECIT’04, in Grazer Math. Ber.