Reimann, S., Fuster JM, Gierer, A., Mayer-Kress G, Neumann, T., Roelfsema P, Rotter S, Schoner G, Stephan A, Vaadia, E., & Walter, H. (1998). Emergent properties of natural and artificial systems. Zeitschrift für Naturforschung C, 53(7-8), 770-774. Retrieved from http://www.znaturforsch.com/ac/v53c/c53c.htm.