1. Arena, P. (1994). Neural networks for modelling and identifiction in circuits and systems. PhD Thesis, DEES, University of Catania, Italy.
2. Arena, P., Fortuna, L., Re, R., & Xibilia, M.G. (1993). On the capability of neural networks with complex neurons in complex valued function approximation. Proceedings IEEE International Conference on Circuits and Systems (pp. 2168–2171). Chicago.
3. Arena, P., Fortuna, L., & Xibilia, M.G. (1994a). Predicting complex chaotic time series via complex valued MLPs IEEE International Conference on Circuits and Systems, London.
4. Arena, P., Fortuna, L., Occhipinti, L., & Xibilia, M.G. (1994b). Neural Networks for quaternion valued function approximation. Proceedings of IEEE International Symposium on Circuit and Systems, Vol. 6 (pp. 307–310). London.
5. Arena, P., Baglio, S., Fortuna, L., & Xibilia, M.G. (1995). Chaotic time-series prediction via quaternionic MLPs. Proceedings IEEE International Conference on System Man and Cybernetics (pp. 1790–1794). Vancouver, Canada.