1. Regulated Rewriting in Formal Language Theory
2. R. Freund, O.H. Ibarra, Gh. Păun, and H.C. Yen, Matrix languages, register machines, vector addition systems, inProceedings of the Third Brainstorming Week on Membrane Computing, M.A. Gutiérrez-Naranjo, A. Riscos-Núñez, F.J. Romero-Campero, and D. Sburlan, eds., Fénix Editora, Seville, 2005, pp. 155–168. Available at http://www.gcn.us.es/3BWMC/bravolpdf/bravol155.pdf.
3. The conformon-P system: a molecular and cell biology-inspired computability model