Khan, S. , Zeki, M. , Hameed, S. , Alam, A. , Abdalla, A. , Salami, A. , Lawal, W.. "Signal Generator Circuit Carrying Information as Embedded Features from Multi-Transducer Signals". World Academy of Science, Engineering and Technology, Open Science Index 22, International Journal of Electronics and Communication Engineering, (2008), 2(10), 2199 - 2202.