R. Freund, M. Oswald, A. Paun:
"Extended Gemmating P Systems are Computationally Complete with Four Membranes";
Talk: DCFS (Descriptional Complexity of Formal Systems), London, Ontario, Canada; 2004-07-26 - 2004-07-28; in: "Pre-proceedings DCFS 2004, Western University, London, Ontario, Canada, 2004", L. Ilie, D. Wotschke (ed.); (2004), 24 - 33.