R. Freund, M. Oswald, T. Schirk:
"How a membrane agent buys goods in a membrane store";
Talk: BIC-TA 2006, Wuhan, China; 2006-09-18 - 2006-09-22; in: "Pre-proc. of Int. Conf. on Bio-Inspired Computing - Theory and Applications, BIC-TA 2006, Membrane Computing Section", L. Pan, Gh. Paun (ed.); (2006), 93 - 102.