J. Storck, S. Hochreiter, and J. Schmidhuber. Proceedings of the International Conference on Artificial Neural Networks, Paris, 2, page 159--164. EC2 & Cie, (1995)
J. Zhao, and J. Schmidhuber. From Animals to Animats 4: Proceedings of the Fourth International Conference on Simulation of Adaptive Behavior, Cambridge, MA, page 516--525. MIT Press, Bradford Books, (1996)
A. Graves, S. Fernández, and J. Schmidhuber. Artificial Neural Networks: Biological Inspirations - ICANN 2005, LNCS 3697, page 799--804. Springer-Verlag Berlin Heidelberg, (2005)