P. Mandic, “Complex Valued Recurrent Neural Networks for Noncircular Complex Signals,” International Joint Conference on Neural Networks, 14-19 June 2009, pp. 1987-1992. doi:10.1109/IJCNN.2009.5178960
 T. Adali and H. Li, “A Practical Formulation for Computation of Complex Gradients and its Application to Maximum Likelihood ICA,” 2007 IEEE International Conference on Acoustics, Speech and Signal Processing, Vol. 2, 2007, pp. II-633-II-636. doi:10.1109/ICASSP.2007.366315
 D. P. Xu, H. S. Zhang and L. J. Liu, “Convergence Analysis of Three Classes of Split-Complex Gradient Algorithms for Complex-Valued Recurrent Neural Networks,” Neural Computation, Vol. 22, No. 20, 2010, pp. 2655-2677. doi:10.1162/NECO_a_00021
 G. Zimmermann, A. Minin and V. Kusherbaeva, “Historical Consistent Complex Valued Recurrent Neural Network,” Lecture Notes in Computer Science, Part 1, Vol. 6791, 2011, pp. 185-192. doi:10.1007/978-3-642-21735-7_23
 H.-G. Zimmermann, A. Minin and V. Kusherbaeva, “Comparison of the Complex Valued and Real Valued Neural Networks Trained with Gradient Descent and Random Search Algorithms,” 19th European Symposium on Artificial Neural Networks, Bruges, 27-29 April 2011, pp. 216-222.
 P. Kalra, A. Gangal and D. Chauhan, “Performance Evaluation of Complex Valued Neural Networks Using Various Error Functions,” World Academy of Science, Engineering and Technology, Vol. 29, 2007, pp. 27-32.
 H. L. Li and T. Adali, “A Class of Complex ICA Algorithms Based on the Kurtosis Cost Function,” IEEE Transactions on Neural Networks, Vol. 19, No. 3, 2008, pp. 408-420. doi:10.1109/TNN.2007.908636