Kazutaka Someya Hidekazu Shinozaki Yoshifumi Sekine Pulse-type hardware chaotic neuron model and its bifurcation phenomena. 153-161 1999 12 Neural Networks 1 http://dx.doi.org/10.1016/S0893-6080(98)00099-9 db/journals/nn/nn12.html#SomeyaSS99