Bhattacharyya, S. , Dutta, P. , Maulik, U. , Nandi, P.. "Multilevel Activation Functions For True Color Image Segmentation Using a Self Supervised Parallel Self Organizing Neural Network (PSONN) Architecture: A Comparative Study". World Academy of Science, Engineering and Technology, Open Science Index 8, International Journal of Computer and Information Engineering (2007), 1(8), 2452 - 2464.