1. Bernardini, F., 2002. Analisi Dinamica di Sistemi a Membrane. Tesi di Laurea in Informatica, Universitá di Pisa.
2. Bernardini, F., Manca, V., 2002. P systems with boundary rules. In: Preliminary Proceedings of Second Workshop on Membrane Computing. Curtea de Arges, pp. 97–101.
3. Discrete dynamics in biological models;Bonanno;Rom. J. Inf. Sci. Technol.,2002
4. Generalized stream X-machines and cooperating distributed grammar systems;Gheorghe;Formal Aspects Comput.,2000
5. Kauffman, S.A., 1999. Investigations. Oxford University Press, Oxford.