Rudolf Freund Mihai Ionescu Marion Oswald Extended Spiking Neural P Systems with Decaying Spikes and/or Total Spiking. 1223-1234 2008 19 Int. J. Found. Comput. Sci. 5 http://dx.doi.org/10.1142/S0129054108006248 db/journals/ijfcs/ijfcs19.html#FreundIO08